An ipad/mac book air will be crap at crunching a DVD, encryption and other tasks where real throughput is required.
Horses for courses.
Steve Jobs will kill off the optical drive long before DVD crunching will ever be needed. Whatever short comings the A6 will have (and I'm sure there will be plenty) I think icloud could evolve into something that fills in the (heavy lifting) gaps.
Single core performance hasn't slowed down at all. The difference is that a single core now does a lot more work per clock signal.
You touch on the voltage issue which is really important to grasp. There are processors out there running on as little as 1.2 volts DC to control power consumption. Not to confuse people even more but in a DC resistive circuit power varies with the square of the voltage.
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Originally Posted by Shrike
This is actually a pretty good observation. Yes, single core, single-threaded performance has slowed down.
One wrinkle you forget about is that Intel's Core-i7 CPUs can "turbo". Depending on the workload and the temperature, a multi-core i7 can shut down all but one core and ramp up the clock 20% or so. Not a 2x, but it illustrates why the MHz race is ended.
CPU power (Watts) = number transistors x capacitance per transistor x frequency x voltage^2
These parameters are also correlative as well. In order to get a larger number of higher frequency parts from your fab process, you have to typically increase the input voltage. But look at the equation: f x V^2. Increases in frequency through voltage increases CPU power (essentially heat for this discussion) by more than the square of the voltage increase. It could even be a cubic increase depending on the frequency increase.
This is in of itself not a huge deal if we happen to have really cheap power. A 500 W CPU running at 6 GHz is possible. But you have to suffer the consequences. A super noisy, huge cooling system and the energy costs for powering the thing for any length of time.
Half a decade ago, Intel realized this was not a tenable thing for personal computers, and abandoned their Netburst architecture and moved on to Core. Once that decision was made, single core performance slowed down and the pressure is now on the software to take advantage of the cores.
Do you really think that article is based on fact? I don't take it that way at all, but rather see it as somebody blowing hot air to justify his job.
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Originally Posted by Commodification
I think the fact that Apple might be considering merging mobile iOS devices and Mac OS X imacs and laptops into a single platform is related to some of the limitations of PC processors ability to offer any real new advantages for the majority of users.
You are totally blowing my mind here. How in the hell do you come to this conclusion? The facts are actually just the opposite. Sandy Bridge and Ivy Bridge are huge advancements for the average user. Look at what you get on one chip. You get multiple CPUs, a GPU complex, and some special purpose video hardware. Plus a few more advanced instructions to chew on. Simply put it would be impossible to build a MBA like we have today five years ago.
I don't mean to be cruel here but it appears that you have been very misinformed about computer technology for some time. Either that or you have a pessimistic or negative attitude.
Look at it this way I don't know what Apple is up to with ARM hardware nor do I know their future plans. In fact no body on these forums know except for the Apple engineer here or there. However I can tell you with some certainty that an ARM based MBP would go over like a lead ballon. Now Apple might have plans for an iOS device with keyboard, but I'd think they would carefully market it as an iOS device.
The CPU technology has started to plateau on the 2-3.5 Ghz area so more effort is being put into CPU design
I find these statements frustrating because technology isn't clock rate per say. The problem isn't with the switching of transistors, which happens very fast on modern processors, but rather the ability to move those signals across the die.
Beyond that CPU technology consists of a number of things that have to come together to build a successful processor. Logic design, processes, manufacturing equipment all work together to produce a functioning unit. What clock rate it runs at is determined by the process and the logic design. However that is still only part of the story as more and more is done per clock on modern processors.
Look at it this way, when was the last time you heard somebody complain about the clock rate on his Sandy Bridge machine relative to his old NetBurst machine?
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which allows CPU's like the A6 to delivery performance required to give a similar feel to a PC's response yet use far less power and produce less heat.
When we actually have shipping ARM base Macs we can discuss apparent performance. However I have no doubt in my mind that the mystery A6 will be totally out classed by the then current Intel processor. We aren't talking trivial differences in capability here at all. An Intel based laptop can easily run four hardware based threads with great efficiency.
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An ipad/mac book air will be crap at crunching a DVD, encryption and other tasks where real throughput is required.
Horses for courses.
Well yeah and that is why I don't think Apple would ever market an ARM based MBP. Well at least not until the ARM architecture catches up with Intel in several areas. Also Intel has a fairly well fleshed out 64 bit processor now. Thus they can put effort into optimization, new instructions and other things that can leverage all the transistors they have.
Single core performance hasn't slowed down at all. The difference is that a single core now does a lot more work per clock signal.
I think it has slowed down quite a bit. With turbo-boost, it has mitigated some of the slow-down, but we're not where we should be if frequency ramps were as freely available as they used to be before the power wall was hit.
You're only eeking out about 15%, maybe 20% per clock in single-threaded performance these days. I'll have to go look, but I don't think we are getting 2x performance increases in single threaded performance every 2 years any more.
Look at the performance of Sandy Bridge based Macs versus what was before them. There are some benchmarks already that demonstrated pretty clearly that we are seeing a significant performance boost at the same relative clock rates.
In the case of Apple they are aggressively focusing on low power systems so yeah they bias their hardware to lower clock rate chips. However some of those SB chips can boost clock rate significantly.
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Originally Posted by Shrike
I think it has slowed down quite a bit. With turbo-boost, it has mitigated some of the slow-down, but we're not where we should be if frequency ramps were as freely available as they used to be before the power wall was hit.
When Intel was hell bent on scaling clock rate a few years ago each generation of chips actually ended up performing worst, relative to older models at a given clock rate. I'm not sure where you got the idea that processor performance has been going backwards as it hasn't been. WE are getting much better performance out of each core in a chip these days.
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You're only eeking out about 15%, maybe 20% per clock in single-threaded performance these days.
I'm not sure what you mean by that statement. I've never heard of such a performance metric.
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I'll have to go look, but I don't think we are getting 2x performance increases in single threaded performance every 2 years any more.
When was the last time that happened? There was a time, back in the 486 days, when you could double clock rate and keep up with improved memory systems. Those days are gone. The reality is that today it actually takes a very long time to get a few bytes of data from RAM as RAM is electrically a very long ways away from the CPU cores.
I just don't see where you get any information to support your position. The reality is that increasing the clock rate doesn't scale well because you still need to be able to scale the rest of the system. Focusing on bottle necks, like Apple did with the AIRs, now has a greater impact on performance.
I think it has slowed down quite a bit. With turbo-boost, it has mitigated some of the slow-down, but we're not where we should be if frequency ramps were as freely available as they used to be before the power wall was hit.
You're only eeking out about 15%, maybe 20% per clock in single-threaded performance these days. I'll have to go look, but I don't think we are getting 2x performance increases in single threaded performance every 2 years any more.
You really have to restrict what you are talking about to make a statement like that. CPus aren't a single thread execution units anymore, they are complex systems which also optimize far more on memory accesses and support. You have to falsely construct a current argument based on a 10 year old view of a CPU or you have to acknowledge that throughput is going up by 4x or more every 2 years.
CPUs have been held back by comparatively poor memory system design and execution for far too long, now that part of the CPU capability equation is being fixed. There is so much pent up underperformance that throughput increases will exceed what most folks incorrectly think of as the Moores' Law curve for quite awhile yet. Finally, engineers are freed from the sexy Mhz marketing forcing engineers to focus on that, and Mhz has has finally slipped back to an engineering driven priority. A relatively low priority in the big picture.
Moore's law is more an economic law than physical or computational. It's about computational power at a given price. It may be that typical consumer-level computers are not getting better as quickly, but we're not spending as much on computers as we used to. That computing power is also being distributed, not just on multiple cores but on GPUs.
Anyway, integrated circuits aren't going to be the preferred method of computing forever. Once we reach their limit, we'll find something else. That's a long ways away, regardless.
2020 will be about the time 3D integrated circuits become standard and that will carry us into whatever new paradigm awaits in 2030 (optical or quantum computing).
Moore's law is more an economic law than physical or computational. It's about computational power at a given price. It may be that typical consumer-level computers are not getting better as quickly, but we're not spending as much on computers as we used to. That computing power is also being distributed, not just on multiple cores but on GPUs.
No. No. A thousand times no.
Moore's Law relates that production transistor densities on Integrated Circuits tend to double per unit area every year to 18 months, at essentially constant production cost.
That's it.
Everything else people attribute to Moore's Law is not actually part of the observation that commented on the physical nature of IC production. There is no solid predictable correlation between the secondary effects of having more transistors per unit area and the greater density itself beyond an IC becomes more powerful if you throw more transistors into it. How you use those transistors have everything to do with specifically how powerful and how much throughput you can get out of an IC.
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Anyway, integrated circuits aren't going to be the preferred method of computing forever. Once we reach their limit, we'll find something else. That's a long ways away, regardless.
2020 will be about the time 3D integrated circuits become standard and that will carry us into whatever new paradigm awaits in 2030 (optical or quantum computing).
No, ICs will continue to be the foundation of computing for the far foreseeable future. The construction methods and circuit components of those IC is what will change.
Quantum computing is not an exact science and does not produce exact results, only probabilities. Intermediate steps do not exist and changes are state destructive, making algorithms hard to describe and even harder to implement. So you have to run your computation many times to confirm that the probabilities are generating a useful answer. It's decades off at best from being widely useful, and the chance all of us will be housing near absolute zero enclosures for our qbits at home and at work is even less likely and farther off.
The facts are actually just the opposite. Sandy Bridge and Ivy Bridge are huge advancements for the average user. Look at what you get on one chip. You get multiple CPUs, a GPU complex, and some special purpose video hardware. Plus a few more advanced instructions to chew on. Simply put it would be impossible to build a MBA like we have today five years ago.
Yet the vast majority of people on this planet could care less and will instead continue to migrate to mobile devices as their main computer.
Look at the performance of Sandy Bridge based Macs versus what was before them. There are some benchmarks already that demonstrated pretty clearly that we are seeing a significant performance boost at the same relative clock rates.
On aggregate Sandy Bridge is about 0% to 20% faster per core than Westmere/Clarkdale/Lynfield/etc processors at the same clock rate, with a lot more towards the 0% end of the range. The performance increase wasn't that significant. What was significiant was the price. Sandy Bridge chips came in a lot lower than then the previous gen chips.
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When Intel was hell bent on scaling clock rate a few years ago each generation of chips actually ended up performing worst, relative to older models at a given clock rate. I'm not sure where you got the idea that processor performance has been going backwards as it hasn't been. WE are getting much better performance out of each core in a chip these days.
Didn't say backwards. I said slowed compared to the days where frequency ramps were free.
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I'm not sure what you mean by that statement. I've never heard of such a performance metric.
Single-threaded benchmarks? Kind of hard to believe you have not hard of these.
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When was the last time that happened? There was a time, back in the 486 days, when you could double clock rate and keep up with improved memory systems. Those days are gone. The reality is that today it actually takes a very long time to get a few bytes of data from RAM as RAM is electrically a very long ways away from the CPU cores.
When superscalar was introduced with frequency ramp. When OOE was introduced along with a frequency ramp. I'll have to look up some others. As an example: 486 to Pentium. Pentium to Pentium Pro. Yeah, the days of getting 2x single threaded performance are long gone.
Improving single threaded performance will improve every single application.
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I just don't see where you get any information to support your position. The reality is that increasing the clock rate doesn't scale well because you still need to be able to scale the rest of the system. Focusing on bottle necks, like Apple did with the AIRs, now has a greater impact on performance.
Yes, very true. I'll get to the other thing in a different post.
You really have to restrict what you are talking about to make a statement like that. CPus aren't a single thread execution units anymore, they are complex systems which also optimize far more on memory accesses and support. You have to falsely construct a current argument based on a 10 year old view of a CPU or you have to acknowledge that throughput is going up by 4x or more every 2 years.
CPUs have been held back by comparatively poor memory system design and execution for far too long, now that part of the CPU capability equation is being fixed. There is so much pent up underperformance that throughput increases will exceed what most folks incorrectly think of as the Moores' Law curve for quite awhile yet. Finally, engineers are freed from the sexy Mhz marketing forcing engineers to focus on that, and Mhz has has finally slipped back to an engineering driven priority. A relatively low priority in the big picture.
My worldview is the improving single-threaded performance is the single biggest benefit to the user. Every single application will have improved performance if single-threaded performance increase. That's why I harp on it here. With multi-cores, only some applications will see improvements.
I totally agree with you that system throughput is increasing in concert with the transistor budgets, but benefits to the end user, in single-threaded ops? Not so much.
The core counts and transistor counts will continue upward apace. But the software is still lagging quite a bit. Multithreaded software is hard and not every operation could be multi-threaded. I think the vast majority of software out there is largely of the single-threaded variety - or it could be multithreaded, but one thread serves as the bottleneck to performance - and having more and more cores will not help.
Today, 4 cores is normal and our software barely takes advantage of that. Tomorrow, when 6/8/10/12-cores are available? The benefits aren't going to be that much.
On aggregate Sandy Bridge is about 0% to 20% faster per core than Westmere/Clarkdale/Lynfield/etc processors at the same clock rate, with a lot more towards the 0% end of the range. The performance increase wasn't that significant. What was significiant was the price. Sandy Bridge chips came in a lot lower than then the previous gen chips.
Ahh but the systems benchmark much better. Of course half of that is people picking benchmarks that play to SB strength.
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Didn't say backwards. I said slowed compared to the days where frequency ramps were free.
I lost track of this thread but you do realize those frequency ramps of the past where for marketing. Intels old chips actually performed worst on a cycle by cycle basis for awhile.
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Single-threaded benchmarks? Kind of hard to believe you have not hard of these.
I've heard of them but my point is they are of limited use considering how modern users use their machines and how today's software is written. Let's face it it is exceedingly easy to get a Mac to multitask these days even for novice users. That is at the system level, at the app level it is a whole new ball game.
For example Safari is heavily threaded but also spawns processes for things like Flash. Not to mention Safari uses GPU acceleration. It isn't so much that I dismiss single threaded benchmarks is just that they are of little value to today's user.
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When superscalar was introduced with frequency ramp. When OOE was introduced along with a frequency ramp. I'll have to look up some others. As an example: 486 to Pentium. Pentium to Pentium Pro. Yeah, the days of getting 2x single threaded performance are long gone.
For general purpose instructions yes! However Intel can now apply all of those free transistors to special purpose hardware. So today's processors can do things no processor of the past could - for example decode video in realtime.
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Improving single threaded performance will improve every single application.
Not at the expense of cores it won't. Take our Safari example, turn off all the cores but one and see what happens. This isn't to say certain single thread apps don't exist just that you put to much emphasis on single threading.
The big problem with stressing single thread performance is the diminishing returns for the engineering effort put in. In any event I suspect we will be seeing some creep up in clock rates as Intel and AMD move to smaller process geometries. AMD can already hit 4GHz speed stepping.
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Yes, very true. I'll get to the other thing in a different post.
The unfortunate thing is that it looks like flash is already hitting the wall.
My worldview is the improving single-threaded performance is the single biggest benefit to the user. Every single application will have improved performance if single-threaded performance increase. That's why I harp on it here. With multi-cores, only some applications will see improvements.
Not to be unkind but you don't know what you are talking about. The transition to dual core was one of the best things that ever happened to the PC industry.
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I totally agree with you that system throughput is increasing in concert with the transistor budgets, but benefits to the end user, in single-threaded ops? Not so much.
It is only a problem if you buy into the mis-belief that single threaded performance is important these days. The fact is today's users would be extremely frustrated with the current selection of apps and the OS's they run on if the machines where single core.
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The core counts and transistor counts will continue upward apace. But the software is still lagging quite a bit. Multithreaded software is hard and not every operation could be multi-threaded. I think the vast majority of software out there is largely of the single-threaded variety - or it could be multithreaded, but one thread serves as the bottleneck to performance - and having more and more cores will not help.
The above is about as valid as the guys that claim OpenCL is a failure. It also indicates a fundamental misunderstanding of how modern OS's and apps work. Honestly you need to look into the modern apps an OS technologies.
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Today, 4 cores is normal and our software barely takes advantage of that. Tomorrow, when 6/8/10/12-cores are available? The benefits aren't going to be that much.
The above is very misleading. It is simply a question of what the user is doing.
Not to be unkind but you don't know what you are talking about. The transition to dual core was one of the best things that ever happened to the PC industry.
Who said it wasn't?
We're spending a bit time on this based on one simple statement, or maybe statements: single threaded performance increases have slowed in the multi-core era, and most software performance is bound to one thread.
The performance increases, the ones most users see and feel and when using an OS, aren't as apparent or as great from CPU generation to generation to be because of this. It used to be great to see every facet of a new computer to be so much faster.
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It is only a problem if you buy into the mis-belief that single threaded performance is important these days. The fact is today's users would be extremely frustrated with the current selection of apps and the OS's they run on if the machines where single core.
If all the transistors in today's multi-core CPUs were devoted to single-threaded performance, and real single-threaded performance improvements were delivered, I think users would be extremely happy, happier than they are today with multi-cores. There's only a small class of users (servers, computational modeling, simulation et al) who need a lot of cores.
Obviously though, CPU architects have run out of techniques to increase single threaded performance 2x every 18-24 months (be it power limits, cost limits, technical limits), and have resorted to using multi-core design.
For today, it's arguable that the best upgrade a user could do is to upgrade to an SSD. Not more RAM. Not a faster CPU.
We're spending a bit time on this based on one simple statement, or maybe statements: single threaded performance increases have slowed in the multi-core era, and most software performance is bound to one thread.
This is where we have a problem and is where I think you are completely wrong. Software performance is seldom bound to one thread any more. Really all you need to do is look at popular software today that most users run from time to time. All of it is making use of threading or traditional UNIX'y processes. Mail, Safari, Finder and frankly just about everything that comes with OS/X.
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The performance increases, the ones most users see and feel and when using an OS, aren't as apparent or as great from CPU generation to generation to be because of this. It used to be great to see every facet of a new computer to be so much faster.
This is not my experience at all. Cores can have a major impact on performance of many apps. And if not with the apps they keep your machine functioning well with multiple apps without degradation.
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If all the transistors in today's multi-core CPUs were devoted to single-threaded performance, and real single-threaded performance improvements were delivered, I think users would be extremely happy, happier than they are today with multi-cores.
Frankly this is baloney. Engineer of cores eventually reaches a point where there is little pay off for those extra transistors. In the end your only hope is a higher clock rate or more cores. Intel is delivering both of these as process technology improve.
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There's only a small class of users (servers, computational modeling, simulation et al) who need a lot of cores.
This is baloney also. It is very much a question of what the user does and that frankly verys widely. To put it mildly it doesn't take much effort these days to put four of more cores to work.
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Obviously though, CPU architects have run out of techniques to increase single threaded performance 2x every 18-24 months (be it power limits, cost limits, technical limits), and have resorted to using multi-core design.
After a bit what more can you do to an adder, multiplier or instruction decode unit? Given that; both AMD and Intel are still making modest gains in performance to traditional instructions.
As to making the user happy that is happening but via specialization in the processors/GPUs. Things like video decode units are huge as they greatly reduce the need to dedicate cores to this task. Also vector units and similar enhancements lead to happy users or in the case of AMD they expect the "GPU" to handle vectors. Either way these are real advancements that enable user functionality that could not be obtained in a traditional ALU no matter how fast it is running.
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For today, it's arguable that the best upgrade a user could do is to upgrade to an SSD. Not more RAM. Not a faster CPU.
Certainly the SSD should be a high priority but many machines/users can benefit from more RAM.
If this was a car, would it be equal to installing two separate motors to increase performance because the law of diminishing returns makes it cost prohibitive to get a significant performance increase out of a single motor?
If Moore's Law is indeed ending and Heisenberg's Law is beginning, how do you think it will influences Apple products five years from now? Will Mac performance plateau while iOS devices continue to rapidly increase performance with the use of multi-cores until Macs and ios devices have nearly the same performance in 5 years or so?
How many multiple-cores can we go before it becomes redundant?
Moore's law doesn't address performance. Instead it states that the transistor count in an IC doubles every two years.
It will likely be invalidated some day, but it does not yet show signs of abating...
Comments
An ipad/mac book air will be crap at crunching a DVD, encryption and other tasks where real throughput is required.
Horses for courses.
Steve Jobs will kill off the optical drive long before DVD crunching will ever be needed. Whatever short comings the A6 will have (and I'm sure there will be plenty) I think icloud could evolve into something that fills in the (heavy lifting) gaps.
You touch on the voltage issue which is really important to grasp. There are processors out there running on as little as 1.2 volts DC to control power consumption. Not to confuse people even more but in a DC resistive circuit power varies with the square of the voltage.
This is actually a pretty good observation. Yes, single core, single-threaded performance has slowed down.
One wrinkle you forget about is that Intel's Core-i7 CPUs can "turbo". Depending on the workload and the temperature, a multi-core i7 can shut down all but one core and ramp up the clock 20% or so. Not a 2x, but it illustrates why the MHz race is ended.
CPU power (Watts) = number transistors x capacitance per transistor x frequency x voltage^2
These parameters are also correlative as well. In order to get a larger number of higher frequency parts from your fab process, you have to typically increase the input voltage. But look at the equation: f x V^2. Increases in frequency through voltage increases CPU power (essentially heat for this discussion) by more than the square of the voltage increase. It could even be a cubic increase depending on the frequency increase.
This is in of itself not a huge deal if we happen to have really cheap power. A 500 W CPU running at 6 GHz is possible. But you have to suffer the consequences. A super noisy, huge cooling system and the energy costs for powering the thing for any length of time.
Half a decade ago, Intel realized this was not a tenable thing for personal computers, and abandoned their Netburst architecture and moved on to Core. Once that decision was made, single core performance slowed down and the pressure is now on the software to take advantage of the cores.
I think the fact that Apple might be considering merging mobile iOS devices and Mac OS X imacs and laptops into a single platform is related to some of the limitations of PC processors ability to offer any real new advantages for the majority of users.
You are totally blowing my mind here. How in the hell do you come to this conclusion? The facts are actually just the opposite. Sandy Bridge and Ivy Bridge are huge advancements for the average user. Look at what you get on one chip. You get multiple CPUs, a GPU complex, and some special purpose video hardware. Plus a few more advanced instructions to chew on. Simply put it would be impossible to build a MBA like we have today five years ago.
http://blogs.barrons.com/techtraderd...ays-jefferies/
I don't mean to be cruel here but it appears that you have been very misinformed about computer technology for some time. Either that or you have a pessimistic or negative attitude.
Look at it this way I don't know what Apple is up to with ARM hardware nor do I know their future plans. In fact no body on these forums know except for the Apple engineer here or there. However I can tell you with some certainty that an ARM based MBP would go over like a lead ballon. Now Apple might have plans for an iOS device with keyboard, but I'd think they would carefully market it as an iOS device.
I think it is the other way around.
The CPU technology has started to plateau on the 2-3.5 Ghz area so more effort is being put into CPU design
I find these statements frustrating because technology isn't clock rate per say. The problem isn't with the switching of transistors, which happens very fast on modern processors, but rather the ability to move those signals across the die.
Beyond that CPU technology consists of a number of things that have to come together to build a successful processor. Logic design, processes, manufacturing equipment all work together to produce a functioning unit. What clock rate it runs at is determined by the process and the logic design. However that is still only part of the story as more and more is done per clock on modern processors.
Look at it this way, when was the last time you heard somebody complain about the clock rate on his Sandy Bridge machine relative to his old NetBurst machine?
which allows CPU's like the A6 to delivery performance required to give a similar feel to a PC's response yet use far less power and produce less heat.
When we actually have shipping ARM base Macs we can discuss apparent performance. However I have no doubt in my mind that the mystery A6 will be totally out classed by the then current Intel processor. We aren't talking trivial differences in capability here at all. An Intel based laptop can easily run four hardware based threads with great efficiency.
An ipad/mac book air will be crap at crunching a DVD, encryption and other tasks where real throughput is required.
Horses for courses.
Well yeah and that is why I don't think Apple would ever market an ARM based MBP. Well at least not until the ARM architecture catches up with Intel in several areas. Also Intel has a fairly well fleshed out 64 bit processor now. Thus they can put effort into optimization, new instructions and other things that can leverage all the transistors they have.
Single core performance hasn't slowed down at all. The difference is that a single core now does a lot more work per clock signal.
I think it has slowed down quite a bit. With turbo-boost, it has mitigated some of the slow-down, but we're not where we should be if frequency ramps were as freely available as they used to be before the power wall was hit.
You're only eeking out about 15%, maybe 20% per clock in single-threaded performance these days. I'll have to go look, but I don't think we are getting 2x performance increases in single threaded performance every 2 years any more.
In the case of Apple they are aggressively focusing on low power systems so yeah they bias their hardware to lower clock rate chips. However some of those SB chips can boost clock rate significantly.
I think it has slowed down quite a bit. With turbo-boost, it has mitigated some of the slow-down, but we're not where we should be if frequency ramps were as freely available as they used to be before the power wall was hit.
When Intel was hell bent on scaling clock rate a few years ago each generation of chips actually ended up performing worst, relative to older models at a given clock rate. I'm not sure where you got the idea that processor performance has been going backwards as it hasn't been. WE are getting much better performance out of each core in a chip these days.
You're only eeking out about 15%, maybe 20% per clock in single-threaded performance these days.
I'm not sure what you mean by that statement. I've never heard of such a performance metric.
I'll have to go look, but I don't think we are getting 2x performance increases in single threaded performance every 2 years any more.
When was the last time that happened? There was a time, back in the 486 days, when you could double clock rate and keep up with improved memory systems. Those days are gone. The reality is that today it actually takes a very long time to get a few bytes of data from RAM as RAM is electrically a very long ways away from the CPU cores.
I just don't see where you get any information to support your position. The reality is that increasing the clock rate doesn't scale well because you still need to be able to scale the rest of the system. Focusing on bottle necks, like Apple did with the AIRs, now has a greater impact on performance.
I think it has slowed down quite a bit. With turbo-boost, it has mitigated some of the slow-down, but we're not where we should be if frequency ramps were as freely available as they used to be before the power wall was hit.
You're only eeking out about 15%, maybe 20% per clock in single-threaded performance these days. I'll have to go look, but I don't think we are getting 2x performance increases in single threaded performance every 2 years any more.
You really have to restrict what you are talking about to make a statement like that. CPus aren't a single thread execution units anymore, they are complex systems which also optimize far more on memory accesses and support. You have to falsely construct a current argument based on a 10 year old view of a CPU or you have to acknowledge that throughput is going up by 4x or more every 2 years.
CPUs have been held back by comparatively poor memory system design and execution for far too long, now that part of the CPU capability equation is being fixed. There is so much pent up underperformance that throughput increases will exceed what most folks incorrectly think of as the Moores' Law curve for quite awhile yet. Finally, engineers are freed from the sexy Mhz marketing forcing engineers to focus on that, and Mhz has has finally slipped back to an engineering driven priority. A relatively low priority in the big picture.
Anyway, integrated circuits aren't going to be the preferred method of computing forever. Once we reach their limit, we'll find something else. That's a long ways away, regardless.
2020 will be about the time 3D integrated circuits become standard and that will carry us into whatever new paradigm awaits in 2030 (optical or quantum computing).
Moore's law is more an economic law than physical or computational. It's about computational power at a given price. It may be that typical consumer-level computers are not getting better as quickly, but we're not spending as much on computers as we used to. That computing power is also being distributed, not just on multiple cores but on GPUs.
No. No. A thousand times no.
Moore's Law relates that production transistor densities on Integrated Circuits tend to double per unit area every year to 18 months, at essentially constant production cost.
That's it.
Everything else people attribute to Moore's Law is not actually part of the observation that commented on the physical nature of IC production. There is no solid predictable correlation between the secondary effects of having more transistors per unit area and the greater density itself beyond an IC becomes more powerful if you throw more transistors into it. How you use those transistors have everything to do with specifically how powerful and how much throughput you can get out of an IC.
Anyway, integrated circuits aren't going to be the preferred method of computing forever. Once we reach their limit, we'll find something else. That's a long ways away, regardless.
2020 will be about the time 3D integrated circuits become standard and that will carry us into whatever new paradigm awaits in 2030 (optical or quantum computing).
No, ICs will continue to be the foundation of computing for the far foreseeable future. The construction methods and circuit components of those IC is what will change.
Quantum computing is not an exact science and does not produce exact results, only probabilities. Intermediate steps do not exist and changes are state destructive, making algorithms hard to describe and even harder to implement. So you have to run your computation many times to confirm that the probabilities are generating a useful answer. It's decades off at best from being widely useful, and the chance all of us will be housing near absolute zero enclosures for our qbits at home and at work is even less likely and farther off.
The facts are actually just the opposite. Sandy Bridge and Ivy Bridge are huge advancements for the average user. Look at what you get on one chip. You get multiple CPUs, a GPU complex, and some special purpose video hardware. Plus a few more advanced instructions to chew on. Simply put it would be impossible to build a MBA like we have today five years ago.
Yet the vast majority of people on this planet could care less and will instead continue to migrate to mobile devices as their main computer.
Look at the performance of Sandy Bridge based Macs versus what was before them. There are some benchmarks already that demonstrated pretty clearly that we are seeing a significant performance boost at the same relative clock rates.
On aggregate Sandy Bridge is about 0% to 20% faster per core than Westmere/Clarkdale/Lynfield/etc processors at the same clock rate, with a lot more towards the 0% end of the range. The performance increase wasn't that significant. What was significiant was the price. Sandy Bridge chips came in a lot lower than then the previous gen chips.
When Intel was hell bent on scaling clock rate a few years ago each generation of chips actually ended up performing worst, relative to older models at a given clock rate. I'm not sure where you got the idea that processor performance has been going backwards as it hasn't been. WE are getting much better performance out of each core in a chip these days.
Didn't say backwards. I said slowed compared to the days where frequency ramps were free.
I'm not sure what you mean by that statement. I've never heard of such a performance metric.
Single-threaded benchmarks? Kind of hard to believe you have not hard of these.
When was the last time that happened? There was a time, back in the 486 days, when you could double clock rate and keep up with improved memory systems. Those days are gone. The reality is that today it actually takes a very long time to get a few bytes of data from RAM as RAM is electrically a very long ways away from the CPU cores.
When superscalar was introduced with frequency ramp. When OOE was introduced along with a frequency ramp. I'll have to look up some others. As an example: 486 to Pentium. Pentium to Pentium Pro. Yeah, the days of getting 2x single threaded performance are long gone.
Improving single threaded performance will improve every single application.
I just don't see where you get any information to support your position. The reality is that increasing the clock rate doesn't scale well because you still need to be able to scale the rest of the system. Focusing on bottle necks, like Apple did with the AIRs, now has a greater impact on performance.
Yes, very true. I'll get to the other thing in a different post.
You really have to restrict what you are talking about to make a statement like that. CPus aren't a single thread execution units anymore, they are complex systems which also optimize far more on memory accesses and support. You have to falsely construct a current argument based on a 10 year old view of a CPU or you have to acknowledge that throughput is going up by 4x or more every 2 years.
CPUs have been held back by comparatively poor memory system design and execution for far too long, now that part of the CPU capability equation is being fixed. There is so much pent up underperformance that throughput increases will exceed what most folks incorrectly think of as the Moores' Law curve for quite awhile yet. Finally, engineers are freed from the sexy Mhz marketing forcing engineers to focus on that, and Mhz has has finally slipped back to an engineering driven priority. A relatively low priority in the big picture.
My worldview is the improving single-threaded performance is the single biggest benefit to the user. Every single application will have improved performance if single-threaded performance increase. That's why I harp on it here. With multi-cores, only some applications will see improvements.
I totally agree with you that system throughput is increasing in concert with the transistor budgets, but benefits to the end user, in single-threaded ops? Not so much.
The core counts and transistor counts will continue upward apace. But the software is still lagging quite a bit. Multithreaded software is hard and not every operation could be multi-threaded. I think the vast majority of software out there is largely of the single-threaded variety - or it could be multithreaded, but one thread serves as the bottleneck to performance - and having more and more cores will not help.
Today, 4 cores is normal and our software barely takes advantage of that. Tomorrow, when 6/8/10/12-cores are available? The benefits aren't going to be that much.
On aggregate Sandy Bridge is about 0% to 20% faster per core than Westmere/Clarkdale/Lynfield/etc processors at the same clock rate, with a lot more towards the 0% end of the range. The performance increase wasn't that significant. What was significiant was the price. Sandy Bridge chips came in a lot lower than then the previous gen chips.
Ahh but the systems benchmark much better. Of course half of that is people picking benchmarks that play to SB strength.
Didn't say backwards. I said slowed compared to the days where frequency ramps were free.
I lost track of this thread but you do realize those frequency ramps of the past where for marketing. Intels old chips actually performed worst on a cycle by cycle basis for awhile.
Single-threaded benchmarks? Kind of hard to believe you have not hard of these.
I've heard of them but my point is they are of limited use considering how modern users use their machines and how today's software is written. Let's face it it is exceedingly easy to get a Mac to multitask these days even for novice users. That is at the system level, at the app level it is a whole new ball game.
For example Safari is heavily threaded but also spawns processes for things like Flash. Not to mention Safari uses GPU acceleration. It isn't so much that I dismiss single threaded benchmarks is just that they are of little value to today's user.
When superscalar was introduced with frequency ramp. When OOE was introduced along with a frequency ramp. I'll have to look up some others. As an example: 486 to Pentium. Pentium to Pentium Pro. Yeah, the days of getting 2x single threaded performance are long gone.
For general purpose instructions yes! However Intel can now apply all of those free transistors to special purpose hardware. So today's processors can do things no processor of the past could - for example decode video in realtime.
Improving single threaded performance will improve every single application.
Not at the expense of cores it won't. Take our Safari example, turn off all the cores but one and see what happens. This isn't to say certain single thread apps don't exist just that you put to much emphasis on single threading.
The big problem with stressing single thread performance is the diminishing returns for the engineering effort put in. In any event I suspect we will be seeing some creep up in clock rates as Intel and AMD move to smaller process geometries. AMD can already hit 4GHz speed stepping.
Yes, very true. I'll get to the other thing in a different post.
The unfortunate thing is that it looks like flash is already hitting the wall.
My worldview is the improving single-threaded performance is the single biggest benefit to the user. Every single application will have improved performance if single-threaded performance increase. That's why I harp on it here. With multi-cores, only some applications will see improvements.
Not to be unkind but you don't know what you are talking about. The transition to dual core was one of the best things that ever happened to the PC industry.
I totally agree with you that system throughput is increasing in concert with the transistor budgets, but benefits to the end user, in single-threaded ops? Not so much.
It is only a problem if you buy into the mis-belief that single threaded performance is important these days. The fact is today's users would be extremely frustrated with the current selection of apps and the OS's they run on if the machines where single core.
The core counts and transistor counts will continue upward apace. But the software is still lagging quite a bit. Multithreaded software is hard and not every operation could be multi-threaded. I think the vast majority of software out there is largely of the single-threaded variety - or it could be multithreaded, but one thread serves as the bottleneck to performance - and having more and more cores will not help.
The above is about as valid as the guys that claim OpenCL is a failure. It also indicates a fundamental misunderstanding of how modern OS's and apps work. Honestly you need to look into the modern apps an OS technologies.
Today, 4 cores is normal and our software barely takes advantage of that. Tomorrow, when 6/8/10/12-cores are available? The benefits aren't going to be that much.
The above is very misleading. It is simply a question of what the user is doing.
Not to be unkind but you don't know what you are talking about. The transition to dual core was one of the best things that ever happened to the PC industry.
Who said it wasn't?
We're spending a bit time on this based on one simple statement, or maybe statements: single threaded performance increases have slowed in the multi-core era, and most software performance is bound to one thread.
The performance increases, the ones most users see and feel and when using an OS, aren't as apparent or as great from CPU generation to generation to be because of this. It used to be great to see every facet of a new computer to be so much faster.
It is only a problem if you buy into the mis-belief that single threaded performance is important these days. The fact is today's users would be extremely frustrated with the current selection of apps and the OS's they run on if the machines where single core.
If all the transistors in today's multi-core CPUs were devoted to single-threaded performance, and real single-threaded performance improvements were delivered, I think users would be extremely happy, happier than they are today with multi-cores. There's only a small class of users (servers, computational modeling, simulation et al) who need a lot of cores.
Obviously though, CPU architects have run out of techniques to increase single threaded performance 2x every 18-24 months (be it power limits, cost limits, technical limits), and have resorted to using multi-core design.
For today, it's arguable that the best upgrade a user could do is to upgrade to an SSD. Not more RAM. Not a faster CPU.
Who said it wasn't?
We're spending a bit time on this based on one simple statement, or maybe statements: single threaded performance increases have slowed in the multi-core era, and most software performance is bound to one thread.
This is where we have a problem and is where I think you are completely wrong. Software performance is seldom bound to one thread any more. Really all you need to do is look at popular software today that most users run from time to time. All of it is making use of threading or traditional UNIX'y processes. Mail, Safari, Finder and frankly just about everything that comes with OS/X.
The performance increases, the ones most users see and feel and when using an OS, aren't as apparent or as great from CPU generation to generation to be because of this. It used to be great to see every facet of a new computer to be so much faster.
This is not my experience at all. Cores can have a major impact on performance of many apps. And if not with the apps they keep your machine functioning well with multiple apps without degradation.
If all the transistors in today's multi-core CPUs were devoted to single-threaded performance, and real single-threaded performance improvements were delivered, I think users would be extremely happy, happier than they are today with multi-cores.
Frankly this is baloney. Engineer of cores eventually reaches a point where there is little pay off for those extra transistors. In the end your only hope is a higher clock rate or more cores. Intel is delivering both of these as process technology improve.
There's only a small class of users (servers, computational modeling, simulation et al) who need a lot of cores.
This is baloney also. It is very much a question of what the user does and that frankly verys widely. To put it mildly it doesn't take much effort these days to put four of more cores to work.
Obviously though, CPU architects have run out of techniques to increase single threaded performance 2x every 18-24 months (be it power limits, cost limits, technical limits), and have resorted to using multi-core design.
After a bit what more can you do to an adder, multiplier or instruction decode unit? Given that; both AMD and Intel are still making modest gains in performance to traditional instructions.
As to making the user happy that is happening but via specialization in the processors/GPUs. Things like video decode units are huge as they greatly reduce the need to dedicate cores to this task. Also vector units and similar enhancements lead to happy users or in the case of AMD they expect the "GPU" to handle vectors. Either way these are real advancements that enable user functionality that could not be obtained in a traditional ALU no matter how fast it is running.
For today, it's arguable that the best upgrade a user could do is to upgrade to an SSD. Not more RAM. Not a faster CPU.
Certainly the SSD should be a high priority but many machines/users can benefit from more RAM.
http://www.theregister.co.uk/2011/08...trouble_ahead/
Mentions most of the stuff discussed here as well.
If this was a car, would it be equal to installing two separate motors to increase performance because the law of diminishing returns makes it cost prohibitive to get a significant performance increase out of a single motor?
If Moore's Law is indeed ending and Heisenberg's Law is beginning, how do you think it will influences Apple products five years from now? Will Mac performance plateau while iOS devices continue to rapidly increase performance with the use of multi-cores until Macs and ios devices have nearly the same performance in 5 years or so?
How many multiple-cores can we go before it becomes redundant?
Moore's law doesn't address performance. Instead it states that the transistor count in an IC doubles every two years.
It will likely be invalidated some day, but it does not yet show signs of abating...
Graph from wikipedia::
It will likely be invalidated some day, but it does not yet show signs of abating...
It will after Skymont comes out. Smaller than that and you risk electrons jumping across the gates on their own.
Pretty sure that's the size. Might be 7 and smaller; I forget.