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Limited RAM in Apple's A5 chip in iPad 2, iPhone 4S motivated by battery life concerns - Page 2

post #41 of 71
Quote:
Originally Posted by dagamer34 View Post

The obvious reason for more RAM is so that the phone has to spend less energy getting costly resources over a 3G data connection again. It is important to note that all desktop operating systems are different from their mobile counterparts in that desktops can stick data in RAM onto the hard disk to be used later. Sure, there's a penalty when you have to grab that data from the hard disk again instead of RAM, but it's MUCH better than having to access network resources (and on a mobile device, using 3G is the largest penalty there is).

As far as I know, none of the mobile operating systems have virtual memory because they don't want to wear out their Flash chips with continuous read/write cycles. Desktops and laptops don't really have this problem. Even Windows 8 tablets will write data to virtual memory.

So I don't really buy the "less RAM = more power savings" argument on a mobile device. Any savings gained from having less RAM would quickly be wiped out by having to re-download images and other media assets from the web.

Yes because you know more about this subject than the ENGINEERS at 2 of the biggest companies in the world....

I have always said this to my cousin who seems to love the phone with the best specs. I would just say "wats the point of having these 'SUPER GREAT SPECS' if your really not going to use them all that much on the phone, its more efficient to put in the specs NEEDED to perform the tasks that it can"....my point is that all these android fans love their specced out phones but is it really worth it to having a shitload of memory if your batter life is going to be shit? Apple knows how to make use of what they have and somehow still beat out the competiton with better specs, and then to put the their foot a little further up Android's ass they have way better battery life.
post #42 of 71
Quote:
Originally Posted by jmillermcp View Post

Good God man, next time read the freaking article before you go off on a rant. MS was applauding Apple for their memory decisions, not bashing them.

What do you expect. This place is crawling with Apple-fanatic-idiots. There are quite a number of good Apple folks here too.
post #43 of 71
Quote:
Originally Posted by Corporate View Post

Yes because you know more about this subject than the ENGINEERS at 2 of the biggest companies in the world....

I have always said this to my cousin who seems to love the phone with the best specs. I would just say "wats the point of having these 'SUPER GREAT SPECS' if your really not going to use them all that much on the phone, its more efficient to put in the specs NEEDED to perform the tasks that it can"....my point is that all these android fans love their specced out phones but is it really worth it to having a shitload of memory if your batter life is going to be shit? Apple knows how to make use of what they have and somehow still beat out the competiton with better specs, and then to put the their foot a little further up Android's ass they have way better battery life.

There was a time somewhere between Jaguar and Tiger that OS updates actually felt faster on the same hardware (the RISC days with IBM.) Between Tiger and Leopard, with all of the changes it felt as though Apple forgot how to write sleek code. Then SL came, and people thought that with "no new features" it was a flop, until you realized the bloat was gone and the machines were fast again, all without a hardware upgrade.
I truly hope for all of us MS has finally gotten the hint; that good code is better than hardware advances. If so, we all win.
post #44 of 71
Quote:
Originally Posted by Bancho View Post

How do you figure? The article says in the first line that it's built into the processor. It's all contained in the same "chip" though there are multiple dies within that package. It's a semantic issue at best.

Hardly. The price paid for going off die, even within the same package is an access time increase of at least 30x or so. Keeping memory on die will eventually be the way of the future, and it will make computers that 30x or so faster all at once. We've got more than a few years before we get there yet.

The main benefit of packaging the way Apple does is that power requirements are significantly lower because the connections can be better engineered compared to memory off-package connections. Better engineered connections mean less noise and less noise means less signal strength needed which is why the power consumption gets lower.

So no, it's not semantic issues at all. It's hard fact and precise terminology that immediately identifies the performance regimes.
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post #45 of 71
Quote:
Originally Posted by wizard69 View Post

The primary issue (more RAM = more power) is accurate to an extent. Dynamic RAM is especially an issue here as you can't stop refreshing it. However there are extensions and considerations that can tip the scales in a different direction. For example if an app has to spend extensive amounts of time accessing secondary store it can have a greater impact on battery life than limiting RAM. Also pressure on RAM can impact responsiveness of the platform.

Now realize that this is an engineering issue. Each time a process shrink comes along the engineering team has to evaluate where the best place is to get additional advantage from the power savings. That may mean more cores, a better GPU or more RAM. Obviously Apple decided that the weak points in their system architecture was in the CPU and GPU this time around. That might not be the case in the next revision.

Those reasons are why Apple provides so many stock GUI elements. Sharing the graphics makes an order of magnitude or more improvement in memory efficiency. It's also why Apple suspends programs between invocations as the default way to do business. That saves both from eliminating background running code when it isn't necessary as well as further lowering overall memory requirements, which allows less RAM and again less power draw.
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post #46 of 71
Quote:
Originally Posted by hill60 View Post

I remember updating my Mac Plus from 256kb of RAM to an amazing 1Mb.

I did a science degree with that thing, complete with 20Mb hard drive which cost $3000.

A slow poke of a computer by today's standards. On the other hand I just loved that little machine as it highlighted why people would want to have such a machine in the house.

It did however highlight another issue, that is Apples reluctance to offer enough RAam in their machines.
post #47 of 71
Obviously we won't get the area to implement system RAM but we should have enough die space for video RAM for the GPU. Even if it is just a frame buffer it ought to help a great deal with power savings. After all the GPU constantly accesses memory.

I suppose the modern approach would be to make the cache bigger. I'm sure that would lead to an interesting discussion amongst engineers. My thing is that moving to retina type displays in an iPad means a lot of data gets accessed for each screen update. Putting that frame buffer outside of normal memory channels just means less congestion on a regular cache.
Quote:
Originally Posted by Hiro View Post

Hardly. The price paid for going off die, even within the same package is an access time increase of at least 30x or so. Keeping memory on die will eventually be the way of the future, and it will make computers that 30x or so faster all at once. We've got more than a few years before we get there yet.

For anybody interested there is a series on ITunes that goes into chip design. Unfortunately I don't have the exact name but it was offered through Stanford and was part of their computer science offerings.

In a nut shell you pay big time in access speed and power when going off chip. the question for Apple is the move to the 20nm nodes enough of a shrink to provide room for a reasonably sized RAM array. I suspect not, at least not for general system access. Especially after adding cores and other functionality.
Quote:
The main benefit of packaging the way Apple does is that power requirements are significantly lower because the connections can be better engineered compared to memory off-package connections. Better engineered connections mean less noise and less noise means less signal strength needed which is why the power consumption gets lower.

While you are correct on the technology I think the big advantage for Apple is the ability to crunch a 32 bit computer down to the size of the tiny motherboard inside iPhone. In otherwords physical space is a driving force for this type of hardware. That doesn't mean the advantages you point out aren't important as the have a huge impact on the system. It is just that without the stacked dies iPhone would likely be a much fatter device.
Quote:
So no, it's not semantic issues at all. It's hard fact and precise terminology that immediately identifies the performance regimes.

I'm not happy to see people wallow in ignorance either. For the non technical person simply understanding that there are multiple chips in that A5 package ought to be good enough. In the future we may have 3D technologies that obscure the issues here. For now people need to realizes that A5 is a package of chips.
post #48 of 71
Quote:
Originally Posted by SixnaHalfFeet View Post

AppleInsider, Can we get the link to the Microsoft blog? It will help with fact checking. Thanks.

It took me about 15 seconds to google for that link:

http://blogs.msdn.com/b/b8/archive/2...windows-8.aspx

I wonder how you want to do "fact checking" without even being able to find that link yourself.

But then why work yourself when others can do the job for you...
post #49 of 71
The problem with a system that uses dynamic RAM is that it constantly has to be refreshed. That ends up being a significant power draw for something that might spend most of its day in your pocket. I honestly think the guy from Microsoft was addressing those loads that impact idle battery lifetimes. Let's face it when an app is being ran or used the power demand can vary widely and more importantly the user expects power to be used when the app is in use. What the user doesn't like is his cell phone going dead in his pocket.

Now here one has to expect that a device will have significant idle periods which many iOS devices do. The always on nature of most iOS devices though require that idle power be minimized as much as possible.

Quote:
Originally Posted by Hiro View Post

Those reasons are why Apple provides so many stock GUI elements. Sharing the graphics makes an order of magnitude or more improvement in memory efficiency. It's also why Apple suspends programs between invocations as the default way to do business. That saves both from eliminating background running code when it isn't necessary as well as further lowering overall memory requirements, which allows less RAM and again less power draw.
post #50 of 71
Quote:
Originally Posted by Andreas71 View Post

It took me about 15 seconds to google for that link:

http://blogs.msdn.com/b/b8/archive/2...windows-8.aspx

I wonder how you want to do "fact checking" without even being able to find that link yourself.

But then why work yourself when others can do the job for you...

Thanks for helping the tall youngster, Andreas. It's sad really. In the words of Jed Clampett, "pitiful, just pitiful".
post #51 of 71
Quote:
Originally Posted by dagamer34 View Post

The obvious reason for more RAM is so that the phone has to spend less energy getting costly resources over a 3G data connection again. It is important to note that all desktop operating systems are different from their mobile counterparts in that desktops can stick data in RAM onto the hard disk to be used later. Sure, there's a penalty when you have to grab that data from the hard disk again instead of RAM, but it's MUCH better than having to access network resources (and on a mobile device, using 3G is the largest penalty there is).

As far as I know, none of the mobile operating systems have virtual memory because they don't want to wear out their Flash chips with continuous read/write cycles. Desktops and laptops don't really have this problem. Even Windows 8 tablets will write data to virtual memory.

So I don't really buy the "less RAM = more power savings" argument on a mobile device. Any savings gained from having less RAM would quickly be wiped out by having to re-download images and other media assets from the web.

Your comment is wrong on so many levels, it's almost as if you tried.

3G has nothing to do with RAM. The only data being uses over 3G, WiFi, or any other connection is data that could otherwise be stored via Flash, but isn't because it either needs to be fresh data (what is the weather, stock price, news), or because it takes up too much space (the Netflix library, Wikipedia, Google Maps, etc...).

Using 512MB or 1GB of RAM would have no impact on connectivity required resources.

Furthermore, even 3rd party apps are allowed to cache incoming data to Flash, so even assets that are time sensitive, but haven't expired, or are too large, but only represent what was previously needed, can be written and read from Flash.

The bottom line is that this article is spot on. There are multiple reasons for the decision to use less RAM: 1) Cost 2) Power Savings 3) Size 4) Speed. The last point, speed, is a tricky one, because less RAM will actually increase the speed of the device *IF* the upper threshold of memory usage is not reached and is only of practical significance if the amount of installed RAM that you're comparing it against is overkill.
post #52 of 71
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post #53 of 71
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post #54 of 71
Quote:
Originally Posted by mstone View Post

iPhone sure, but the iPad has volumes of unused space that could accommodate a much larger battery to provide the needed power for the additional RAM. It might make it too heavy, but more RAM is better, in my opinion, as long as you can still deliver the long battery life that we currently enjoy on iPad.

no, heavy is not better. use a laptop if you want more ram and weight.
post #55 of 71
Quote:
Originally Posted by Corporate View Post

Yes because you know more about this subject than the ENGINEERS at 2 of the biggest companies in the world....

I have always said this to my cousin who seems to love the phone with the best specs. I would just say "wats the point of having these 'SUPER GREAT SPECS' if your really not going to use them all that much on the phone, its more efficient to put in the specs NEEDED to perform the tasks that it can"....my point is that all these android fans love their specced out phones but is it really worth it to having a shitload of memory if your batter life is going to be shit? Apple knows how to make use of what they have and somehow still beat out the competiton with better specs, and then to put the their foot a little further up Android's ass they have way better battery life.

exactly. this is a big beef with me and android hardware. i could care less if it has a 6 core cpu and 4 gig ram blah, blah, blah, blah. get the f***** battery life and weight in order first!
post #56 of 71
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post #57 of 71
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post #58 of 71
Quote:
Originally Posted by AppleInsider View Post

"In any PC, RAM is constantly consuming power. If an OS uses a lot of memory, it can force device manufacturers to include more physical RAM. The more RAM you have on board, the more power it uses, the less battery life you get.

"Having additional RAM on a tablet device can, in some instances, shave days off the amount of time the tablet can sit on your coffee table looking off but staying fresh and up to date,"

A Macbook Air doesn't last any longer on battery with 1GB RAM than it does with 4GB. If anything, it's the opposite because not being able to maintain data in RAM requires you to download content again and redraw the screen using wifi, CPU, GPU and Flash memory.

There is something to be said for efficient use of memory but a lack of RAM is not something we should hope for. Competing tablets/phones can have lower battery life for any number of reasons - using inefficient code, using highly clocked CPUs and GPUs, Adobe Flash support, larger displays with less efficient illumination methods.

I reckon iPad 3 will have 1GB RAM and I also reckon it won't affect battery life.
post #59 of 71
Quote:
Originally Posted by MacRulez View Post


When Apple adopts true multitasking in iOS 6 the benefits will become self-evident.

Would you be kind enough to explain what you mean by "true multitasking" and why iOS does not have it?

ty
post #60 of 71
Quote:
Originally Posted by wizard69 View Post

The primary issue (more RAM = more power) is accurate to an extent. Dynamic RAM is especially an issue here as you can't stop refreshing it. However there are extensions and considerations that can tip the scales in a different direction. For example if an app has to spend extensive amounts of time accessing secondary store it can have a greater impact on battery life than limiting RAM.

What you say is undoubtedly true of hard drive based systems, but we are talking about the iPhone here and Dynamic RAM will most likely always consume more power than Flash RAM. Therefore accessing secondary storage will most likely have very little power hit (especially if it is just read cycles) compared to the power hit from increasing Dynamic RAM. As the article points out, Dynamic RAM consumes power whether the RAM is being used or not, whether it is actually holding any data or not. Flash RAM only consumes power when an actual read or write is in progress.
post #61 of 71
Quote:
Originally Posted by Marvin View Post

I reckon iPad 3 will have 1GB RAM and I also reckon it won't affect battery life.

I reckon you are correct, but I also reckon that the iPad3 won't be using iPad2 power management or battery size to give the same battery life.
post #62 of 71
Quote:
Originally Posted by MacRulez View Post

Which Android phones have you experienced poor battery life with, and how much did they weigh?

I charge my own about once a day, which doesn't seem terribly inconvenient because I tend to sleep once a day as well.

I don't quite understand the presumption that Apple customers somehow have less access to electrical outlets than the majority who use Android. The demographics of Apple's consumer base would suggest that such basic essentials are not scarce to them, that most even have access to running water as well.

FWIW, my Samsung Galaxy S is actually lighter than the iPhone, not heavier, at 116 grams to the iPhone's 140 grams, though I don't imagine such small differences in weight between phones would produce much in the way of arm strain or back pain.

phone wise: nexus one, htc HD, htc sensation, motorola droid. same gripe: terrible battery life.
weight wise i bled over into android tablets....but same sentiment. screw the specs, build a better designed product all around. thats what apple does.
as far as the samsung galaxy products weight, in particular the tablet, it is acheived with plastic instead of metal. they feel a bit 'cheaper' than apple counterparts.
post #63 of 71
Quote:
Originally Posted by jmmx View Post

Would you be kind enough to explain what you mean by "true multitasking" and why iOS does not have it?

The ability to have your games running in the background as you have a movie running in the background as you type a document as you answer texts.

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post #64 of 71
Quote:
Originally Posted by MacRulez View Post

Do you believe that swapping data between RAM and storage is without energy cost?

No

[QUOTE=MacRulez;1965093Do you believe that network connectivity is without energy cost?[/QUOTE]
No

Quote:
Originally Posted by MacRulez View Post

On most such devices, connectivity is often the second most energy-consuming operation after display. And, not surprisingly, connectivity itself requires RAM.

Of course connectivity, and any other operation, uses RAM, that's not the point. Increasing the RAM from 512MB to 1GB isn't going to have any impact on the amount of 3G usage, that's the point.

As you yourself state, connectivity is second only to display for energy consumption, so accordingly, reading data from storage uses less energy than connectivity (which is not only true, but a whole lot faster as well).

The original point of this thread, which was highly flawed, was that with insufficient RAM, resources would be read / data swapped via 3G, which is just incredibly false.

Whether RAM energy consumption versus needing to swap resources and data to flash consumes more energy is a worthy debate for any specific platform. If you're an engineer on the project could argue that the platform either can stay under the memory threshold for energy savings or would go over.

Looking at the iPhone now as a user, it's speculative as a whole, but as an individual, I've witnessed very little swapping of data and resources do to memory limitations on iOS 4. I'm jailbroken and have monitored my memory use. If iOS 5 uses the same or less memory, then it makes sense, for me, that 512MB would use less power than 1GB.
post #65 of 71
Quote:
Originally Posted by wizard69 View Post

The problem with a system that uses dynamic RAM is that it constantly has to be refreshed. That ends up being a significant power draw for something that might spend most of its day in your pocket. I honestly think the guy from Microsoft was addressing those loads that impact idle battery lifetimes. Let's face it when an app is being ran or used the power demand can vary widely and more importantly the user expects power to be used when the app is in use. What the user doesn't like is his cell phone going dead in his pocket.

Now here one has to expect that a device will have significant idle periods which many iOS devices do. The always on nature of most iOS devices though require that idle power be minimized as much as possible.

Memristors can't get here fast enough. Ridiculously fast, single feature persistent storage doing the job of 6 transistors in a SRAM IC.

Purdue also stumbled on some neat persistent no power when not in use memory too, but it's between flash and DRAM in speed.

I don't expect memristors to be routine for around 10 years though, maybe some prototype stuff with it 5 or so. HP and IBM independently found out how to build them repeatably in the past year. Now it's onto production quality and how to incorporate a previously only theoretical circuit element into an IC.
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post #66 of 71
Quote:
Originally Posted by Marvin View Post

A Macbook Air doesn't last any longer on battery with 1GB RAM than it does with 4GB. If anything, it's the opposite because not being able to maintain data in RAM requires you to download content again and redraw the screen using wifi, CPU, GPU and Flash memory.

There is something to be said for efficient use of memory but a lack of RAM is not something we should hope for. Competing tablets/phones can have lower battery life for any number of reasons - using inefficient code, using highly clocked CPUs and GPUs, Adobe Flash support, larger displays with less efficient illumination methods.

I reckon iPad 3 will have 1GB RAM and I also reckon it won't affect battery life.

The difference is completely obviated by the power cord. The power draws really aren't that different from 1GB to 4GB in an absolute sense. But when you put the system on a hard power budget at the milli level, not the 15 Amp 1500 W/H level those little differences become very significant.

Now spread that relatively very significant fixed milli-budget difference over a week with a source that gets less efficient as it gets depleted and we magnify power draw differences even more.

The reason a potential 1GB iPad3 won't affect apparent battery life is that other places will be engineered to offset, like add a little more battery mass and manufacture the greater amount of RAM in the next smaller stepping to reduce it's power consumption by a third or so. The Apple engineers know with with pretty good certainty what the state of the art for iPad3 production will give in power performance because Apple isn't operating on the bleeding edge. They are adapting well known tech into previously unused configurations because they have a product that supports the R&D for the relatively new production configurations.
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post #67 of 71
I'm going to ignore the latent Microsoft and Windows bashing. What I find interesting is that traditionally, the screen has been the biggest power hog in most modern electronics. Clearly robust processors with numerous cycles and extended memory are also a factor (as anyone who has ever done significant overclocking will tell you) in sucking battery, but I'm sort of shocked that RAM is that big of a factor. I guess it certainly is a bigger factor than the screen in the "sitting on your coffee table" mode described in the article, but on, wouldn't the display be the issue?
post #68 of 71
Quote:
Originally Posted by ddo2 View Post

I'm going to ignore the latent Microsoft and Windows bashing. What I find interesting is that traditionally, the screen has been the biggest power hog in most modern electronics. Clearly robust processors with numerous cycles and extended memory are also a factor (as anyone who has ever done significant overclocking will tell you) in sucking battery, but I'm sort of shocked that RAM is that big of a factor. I guess it certainly is a bigger factor than the screen in the "sitting on your coffee table" mode described in the article, but on, wouldn't the display be the issue?

The RAM is an issue because it draws power at a more or less constant rate even when the screen is off and the processor is sleeping. If you are actively using the device RAM power draw is not a significant issue, but the hours and hours you aren't using it are where it is a big deal.
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post #69 of 71
Sorry but this is a pet peeve of mind. Flash is not accessed randomly and in fact is more disk like than RAM like.

Quote:
Originally Posted by SixnaHalfFeet View Post

What you say is undoubtedly true of hard drive based systems, but we are talking about the iPhone here and Dynamic RAM will most likely always consume more power than Flash RAM.

I suspect it would be more correct to say it depends upon the app and user.
Quote:
Therefore accessing secondary storage will most likely have very little power hit (especially if it is just read cycles) compared to the power hit from increasing Dynamic RAM. As the article points out, Dynamic RAM consumes power whether the RAM is being used or not, whether it is actually holding any data or not. Flash RAM only consumes power when an actual read or write is in progress.

Even that is not entirely correct, if it is turned on flash will consume some power. How much that some is will likely depend upon its size. On the whole though flash burns a considerable amount of power during writes which can't be discounted if an app creates data.

As others have pointed out the lack of RAM can cause power usage due to reloading data from the net when it might not have too. The difference in behavior between my old 3G and iPhone 4 was dramatic and directly due to more RAM. I don't deny the validity of this story, I'm just saying that the value in having more RAM is dependent upon usage. Further more RAM can actually extend run times in some situations. Right now I just think Apple is shooting for maximum idle time and cost control more than anything.
post #70 of 71
Quote:
Originally Posted by macslut View Post

No


No



Of course connectivity, and any other operation, uses RAM, that's not the point. Increasing the RAM from 512MB to 1GB isn't going to have any impact on the amount of 3G usage, that's the point.

And your point is wrong. I can see a difference in reload patterns just between my iPad and iPhone 4. More RAM means that Apple doesn't have invalidate page data to free up memory for the page you are going to. This means a greater likely hood that when you hit the back button the page you are going to gets reloaded from RAM not 3G.
Quote:
As you yourself state, connectivity is second only to display for energy consumption, so accordingly, reading data from storage uses less energy than connectivity (which is not only true, but a whole lot faster as well).

So why did you say the above? You are right in the above statement so you have us confused.
Quote:
The original point of this thread, which was highly flawed, was that with insufficient RAM, resources would be read / data swapped via 3G, which is just incredibly false.

I'm not sure how you even came up with that position. 3G comes into play when using net centric apps and yes the lack of RAM can result in re-reading data over 3G. I really don't understand how you can not see that point.
Quote:
Whether RAM energy consumption versus needing to swap resources and data to flash consumes more energy is a worthy debate for any specific platform. If you're an engineer on the project could argue that the platform either can stay under the memory threshold for energy savings or would go over.

one thing we can agree on is that it is not as simple as some would imply. In apples case though they are very biased to minimal memory machines and have been for years. I'm not convinced Apple made the decision based on merits related to power usage. It could simply be an issue of margins.
Quote:
Looking at the iPhone now as a user, it's speculative as a whole, but as an individual, I've witnessed very little swapping of data and resources do to memory limitations on iOS 4. I'm jailbroken and have monitored my memory use. If iOS 5 uses the same or less memory, then it makes sense, for me, that 512MB would use less power than 1GB.

It will vary by user but I suspect you don't know what you think you know.
post #71 of 71
QUESTION.

Apple's loaded like an Russian officer's gun during the siege of Moscow, why don't they do some research into production-quality MRAM to remove any question of power requirements, allowing capacities to skyrocket?

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