"His assumptions were based on public info about the processor, however. Moki has hinted that this info is, at least to some degree, not strictly accurate, and that there are several key 'surprises' about the chip or it's decendents (typically, he was rather obtuse about this!)
Of course, i have no inforation to back my theory up, and i don't totally subscribe to it myself, but if Apple thought that with this chip and the rumoured ppc980 or other 9xx series chips, it could offer a decent advantage over any x86 based machine, it could introduce a x86 based version of OS X whilst reducing the likelihood that it would endanger it's PPC hardware sales. Whether this would come don t releasing it's own x86 machines or offering OS X to third party manufacturers is another matter."
I think that sooner or later, Apple will have to really go after that 98% and that it can't quite do it while it is viewed as 'proprietary.'
The 9XX roadmap seems to finally give PPC the edge over the next few years. And that buys 'Apple Software Co.' time. For what? If PPC kit outperforms Wintel kit in key markets such as workstation, print and video...they're going to keep buying premium priced PPC kit. This gives Apple the chance to have a pop at the Wintel consumer market. No way? They already are. iPod. iTunes 4 by the years end. Apple software on Wintel? No way...? Way?
970 iMacs that might run Wintel 'as fast' as Wintel? Gives access to 'X'. A licensed version of 'X' to Intel/Amd? Key people like Dell? Dell are already selling iPods. Dell has a massive customer base. How about an agnostic OS that can run on PPC and Intel hardware?
I don't see this as something they can do overnight. Certainly NOT while they're moving to 64-bit. Not while they're 'breaking even'. Not while the transition to 'X' is incomplete...(and it is incomplete by a mile in terms of Apple's userbase adoption...despite what Apple says...)
They may build 'x86' in x86 support. If the Wintel market is moving beyond 'x86' then build in support for 'next gen' of Wintel chips. Encourage key developers to begin 'fat compiling' versions which will run PPC/Hammer/Itanium. This could take some time...and may not begin until developers 'frayed' nerves have been soothed with 'X' sales of eg Quark Aqua for a few years.
To me...this is a very long-term Trojan Horse battleplan. And it maybe something fundamental to Panther's gameplan. This maybe the beginning of something new. If the 970 was made for Apple by a player like IBM...what has been ceded in return? Why did Jobs talk at an Intel conference ('He's Pixar's CEO...')? Yeah. That's right...
Apple already make as much from Software/Services/'Other Products' as they do 'power'Mac sales. And with more Apple software and 'other services' coming on line along with 70 plus retail stores at the end of the year...we can expect that number to increase.
We can expect iTunes 4 for Wintel by the end of the year for the 'music store'. If it does for sales what iPod PC has done for 'Mac', sorry, 'Apple' growth then...
This divergent strategy from 'new' Apple hints that you can't go on indefinitely ignoring a hundred million customers with proprietary kit. Alot of PC users are whinging about the fact they can't have a go at 'X' on their computers...or play with iTunes Music Store...or those great iApps...or the iPod...oops...Apple gave them a version 'just for them' and they sell like crazy.
Apple has been increasingly observant of 'open standards' (on their terms) these last few years. I wonder if they will broaden this to 'non-proprietary' Macs? And broader support for other markets from within 'X'..? 'X' for IBM servers...'X' for Intel renderfarms..., 'X' for cheap Wintel Boxes...'X' for PPC workstation markets (As Amorph would say, 'That's where Apple makes its profits...')
Apple have discovered they can make money in a Wintel market. In fact, they now sell more iPods in PC land than they do in Mac land. And they're dominating market share that 'music player market.' How about that...(better than the 2% they play with in Mac land. And it appears their 'new found confidence' is growing...
LBB, how can you argue that a decent-performing PowerPC CPU would be an impetus to migrate to x86? x86 should (and is) a last-ditch effort if the PowerPC can't keep up at all.
Also, how can you argue that an Apple is any LESS proprietary than a Dell? They are equally proprietary, as is every piece of hardware made by Intel, AMD, Western Digital, Micron, etc. Sorry if I sound rude, but it's a real sticking point for me. I've listened to too many morons complaining that "Apple has a monopoly on Apple Macs."
The 970 will bring Macs into performance parity with PCs for ALL tasks, not just a few photoshop filters. There's simply no need to see Mac OS on x86. If that happened, Apple would end up like also-rans OS/2 and BeOS.
As you said, nothing new or remotely interesting, not to me at least. I added a few shots under that shows what kind of accelerating altivec can be capable of.
In this case, I'm thinking more of the efficiency with which the 970 will do 64-bit FP than some notion that it's a new capability.
With an AltiVec implementation the G4 will hold up okay. Depending on the size of your working set we may see little improvement with the 970 @ 1.4 GHz.
But yes, the 970's improvement will be very significant in doing scalar floating point work and anything memory bound.
I heard the makers of Vue (landscape renderer...) said that Apple could really do with beefing up double precision floating points. For more precise rendering. I didn't quite 'get that'.
Can't the Altivec unit do a double precision float? Or is it limited to single precision. Which Vue doesn't support?In fact, I always thought that the Altivec unit could be used as an extra fpu unit.
Sorry, not a clue what I'm talking about here. Paraphrasing and thrashing about wildly some talk I heard from the makers of Vue.
Personally, I know 3D performance could be improved on all platforms. Especially Apple towers.
Maybe somebody could clear up the Vue thing for me.
On those Macdoobie benches...even the low-end 1.4 970 humbles the the 'twice as fast' Pentium 4 at 3 gig. 'Apparently.'
I'm not a techie. (What, you can tell?) But those benches are still wowing me. That's another whole level for the Mac platform... I can see Alias adding to those 25% of customers being Mac.
So...why did Eon think it a problem? Doesn't it allow as accurate colour rendering? Do you get the odd pixel pop?Renders on a Mac always looked pretty good to me...
S'pose it don't matter if we're getting 970 fpu Hell Hounds!!!
Next dumb question...can the 970 do double precision?
So...why did Eon think it a problem? Doesn't it allow as accurate colour rendering? Do you get the odd pixel pop?Renders on a Mac always looked pretty good to me...
S'pose it don't matter if we're getting 970 fpu Hell Hounds!!!
Next dumb question...can the 970 do double precision?
OK, let's get this sorted out:
The G3 and G4 FPUs can do double-precision floating point. They just can't do it very quickly relative to other CPUs. (The G3 is particularly weak at FP at any precision).
The 970 FPU can do double-precision floating point, and it looks to be a significantly better performer than the G4 at this task.
AltiVec can indeed be used as an FPU, but only for single precision (32 bit) floating point. The G4 and the 970 both have dedicated scalar FPUs that can do both single and double precision work.
Double precision FP makes it easier to write rendering routines with a high degree of precision. AltiVec can't accelerate these routines, because it only works in single precision. (This is not to say that it isn't possible to write very accurate single precision renderers, only that hardly any of the commercial companies actually have. They lean on high-performing double-precision hardware instead.) The upshot of this is that if the 970 crunches double-precision floating point numbers significantly faster than the G4 - which has nothing to do with the fact that it's a 64 bit chip - then existing renderers will see a dramatic speedup.
As for 64 bit color, the video card doesn't have to know anything about 64-bit FP color, because the monitor it's driving certainly doesn't. The software could do all the work on the CPU, downsample to 24 bits, and the GPU would be none the wiser. However, if you want to be able to offload any color-dependent processing to the GPU (remember that transparency is a "color"), then it does have to be able to work with 64-bit FP color. No matter what, it'll end up spitting out 24-bit integer color, but the ability to work at a much higher precision and downsample for output will result in noticeably slicker, clearer rendering and compositing output.
The trend now, of course, is to get the GPU to do as much work as possible. I'm not sure which, if any, currently available GPUs support a 64-bit color space, but if they're not here they're coming. John Carmack's been banging this drum for years now, and they listen to him.
A couple of points where I think there is potential confusion...
Quote:
AltiVec can indeed be used as an FPU, but only for single precision (32 bit) floating point. The G4 and the 970 both have dedicated scalar FPUs that can do both single and double precision work.
AltiVec is a vector unit and can only be used for vector operations. Some of those possible operations are on vectors of 4 32-bit floats, but it cannot be used as a scalar floating point unit which is what the term "FPU" is usually refering to. This means to use AltiVec the developer must write vector code, and that is not a standardized process so the code is unique to PowerPC AltiVec processors. Scalar code, on the other hand, is built into C/C++ (and most other languages) and is cross-platform. Most floating point code out there is scalar in nature (i.e. it works on one number at a time) and therefore does not use the AltiVec unit.
There are some tools available to convert scalar code into vector code, but their use is not widespread and they are not tremendously effective.
Quote:
Double precision FP makes it easier to write rendering routines with a high degree of precision. AltiVec can't accelerate these routines, because it only works in single precision. (This is not to say that it isn't possible to write very accurate single precision renderers, only that hardly any of the commercial companies actually have. They lean on high-performing double-precision hardware instead.) The upshot of this is that if the 970 crunches double-precision floating point numbers significantly faster than the G4 - which has nothing to do with the fact that it's a 64 bit chip - then existing renderers will see a dramatic speedup.
Keep in mind that there are more uses for numbers in rendering than just the pixels you end up seeing on the screen. The positions of the vertices, the texel coordinates for the texture, the normal on the vertex, the position of the camera, etc etc etc. The colours are actually a relatively small part of the whole process and in some ways are the least sensitive to precision requirements which is how GPUs have gotten away with relatively low precision on them (until recently).
Precision requirements usually come out of a long sequence of operations, or from places where really large and really small numbers are being combined. There are techniques available to mitigate these problems, but most developers don't bother to use them (or don't know about them). Floating point math is very often used without being fully understood. Sometimes, however, single precision just isn't enough. Sometimes even double precision isn't enough.
Quote:
As for 64 bit color, the video card doesn't have to know anything about 64-bit FP color, because the monitor it's driving certainly doesn't. The software could do all the work on the CPU, downsample to 24 bits, and the GPU would be none the wiser. However, if you want to be able to offload any color-dependent processing to the GPU (remember that transparency is a "color"), then it does have to be able to work with 64-bit FP color. No matter what, it'll end up spitting out 24-bit integer color, but the ability to work at a much higher precision and downsample for output will result in noticeably slicker, clearer rendering and compositing output.
The need for high precision colour mainly comes from doing many blending and lighting passes, and the amount of that being done has been increasing dramatically as the hardware becomes more powerful. The modern GPUs which support floating point buffers (Radeon 9700 and later, geForceFX and later) can output full floating point precision, but cannot display it directly. To be displayed it has to be cut down to 8 or 10 bits per RGB channel. The loss of information in this conversion isn't too important, however, because no further blending will be done and the eye's preceptive limit is somewhere around 8-10 bits per channel. Alternatively the image can be read back from the card at full precision and used elsewhere.
Quote:
The trend now, of course, is to get the GPU to do as much work as possible. I'm not sure which, if any, currently available GPUs support a 64-bit color space, but if they're not here they're coming. John Carmack's been banging this drum for years now, and they listen to him.
Radeon 9700 & later, geForceFX & later. They actually support 32-bit float per channel which is either 96-bit or 128-bit pixels depending on whether the alpha channel is supported/included.
I guess that's why these guys will be buying Apple this year.
Guess the 970's going to be pret-ty good at 3D then.
I can see the power-starved Mac users baying like malnutritioned wolves at the WWDC...(Steve better be careful...) and outside those Apple retail stores... ((Picture of Apple store sales reps throwing the last dual 1.42 G4'e' carcass outside the store to rabid Mac heads. 'That's all we got...we can't make it go any faster...what do you want from us? Speed?' Incensed by the cpu impotence, the Mac-heads are after blood and proceed to savage the poor defenseless tower on the pavements outside...and after trashing the Ive Plastic MDD masterpiece then proceed to bang on the barricaded store doors...snarling and slabbering...'Jeee....ffiiiivvvvuh...')
Thanks to Amorph and Programmer and Co. for their full front assault on my sporadic questions.
I can see the power-starved Mac users baying like malnutritioned wolves at the WWDC...(Steve better be careful...) and outside those Apple retail stores... ((Picture of Apple store sales reps throwing the last dual 1.42 G4'e' carcass outside the store to rabid Mac heads. 'That's all we got...we can't make it go any faster...what do you want from us? Speed?' Incensed by the cpu impotence, the Mac-heads are after blood and proceed to savage the poor defenseless tower on the pavements outside...and after trashing the Ive Plastic MDD masterpiece then proceed to bang on the barricaded store doors...snarling and slabbering...'Jeee....ffiiiivvvvuh...')
The only thing that your forgot about was the pitchforks, torches, and somebody asking for a sacrifice.
This summer is going to be very sweet for the Mac Loyalists.
AltiVec can indeed be used as an FPU, but only for single precision (32 bit) floating point. The G4 and the 970 both have dedicated scalar FPUs that can do both single and double precision work.
Double precision FP makes it easier to write rendering routines with a high degree of precision. AltiVec can't accelerate these routines, because it only works in single precision. (This is not to say that it isn't possible to write very accurate single precision renderers, only that hardly any of the commercial companies actually have. They lean on high-performing double-precision hardware instead.) The upshot of this is that if the 970 crunches double-precision floating point numbers significantly faster than the G4 - which has nothing to do with the fact that it's a 64 bit chip - then existing renderers will see a dramatic speedup.
You gotta give them the whole skinny in layman's terms man ;-). You should have also mentioned that the reason why most all 3D render developers use double precision FP is because it covers up a lot of shoddy and sloppy algorithms.
Here is a link to a VERY knowledgeable programmer for PowerPCs. I've run it by Chris Cox from Adobe and a few other extremely sharp PPC programmers; They only confirmed that the person's reasoning is spot on.
Comments
Of course, i have no inforation to back my theory up, and i don't totally subscribe to it myself, but if Apple thought that with this chip and the rumoured ppc980 or other 9xx series chips, it could offer a decent advantage over any x86 based machine, it could introduce a x86 based version of OS X whilst reducing the likelihood that it would endanger it's PPC hardware sales. Whether this would come don t releasing it's own x86 machines or offering OS X to third party manufacturers is another matter."
I think that sooner or later, Apple will have to really go after that 98% and that it can't quite do it while it is viewed as 'proprietary.'
The 9XX roadmap seems to finally give PPC the edge over the next few years. And that buys 'Apple Software Co.' time. For what? If PPC kit outperforms Wintel kit in key markets such as workstation, print and video...they're going to keep buying premium priced PPC kit. This gives Apple the chance to have a pop at the Wintel consumer market. No way? They already are. iPod. iTunes 4 by the years end. Apple software on Wintel? No way...? Way?
970 iMacs that might run Wintel 'as fast' as Wintel? Gives access to 'X'. A licensed version of 'X' to Intel/Amd? Key people like Dell? Dell are already selling iPods. Dell has a massive customer base. How about an agnostic OS that can run on PPC and Intel hardware?
I don't see this as something they can do overnight. Certainly NOT while they're moving to 64-bit. Not while they're 'breaking even'. Not while the transition to 'X' is incomplete...(and it is incomplete by a mile in terms of Apple's userbase adoption...despite what Apple says...)
They may build 'x86' in x86 support. If the Wintel market is moving beyond 'x86' then build in support for 'next gen' of Wintel chips. Encourage key developers to begin 'fat compiling' versions which will run PPC/Hammer/Itanium. This could take some time...and may not begin until developers 'frayed' nerves have been soothed with 'X' sales of eg Quark Aqua for a few years.
To me...this is a very long-term Trojan Horse battleplan. And it maybe something fundamental to Panther's gameplan. This maybe the beginning of something new. If the 970 was made for Apple by a player like IBM...what has been ceded in return? Why did Jobs talk at an Intel conference ('He's Pixar's CEO...')? Yeah. That's right...
Apple already make as much from Software/Services/'Other Products' as they do 'power'Mac sales. And with more Apple software and 'other services' coming on line along with 70 plus retail stores at the end of the year...we can expect that number to increase.
We can expect iTunes 4 for Wintel by the end of the year for the 'music store'. If it does for sales what iPod PC has done for 'Mac', sorry, 'Apple' growth then...
This divergent strategy from 'new' Apple hints that you can't go on indefinitely ignoring a hundred million customers with proprietary kit. Alot of PC users are whinging about the fact they can't have a go at 'X' on their computers...or play with iTunes Music Store...or those great iApps...or the iPod...oops...Apple gave them a version 'just for them' and they sell like crazy.
Apple has been increasingly observant of 'open standards' (on their terms) these last few years. I wonder if they will broaden this to 'non-proprietary' Macs? And broader support for other markets from within 'X'..? 'X' for IBM servers...'X' for Intel renderfarms..., 'X' for cheap Wintel Boxes...'X' for PPC workstation markets (As Amorph would say, 'That's where Apple makes its profits...')
Apple have discovered they can make money in a Wintel market. In fact, they now sell more iPods in PC land than they do in Mac land. And they're dominating market share that 'music player market.' How about that...(better than the 2% they play with in Mac land. And it appears their 'new found confidence' is growing...
We have been warned.
Lemon Bon Bon
Lemon Bon Bon
Also, how can you argue that an Apple is any LESS proprietary than a Dell? They are equally proprietary, as is every piece of hardware made by Intel, AMD, Western Digital, Micron, etc. Sorry if I sound rude, but it's a real sticking point for me. I've listened to too many morons complaining that "Apple has a monopoly on Apple Macs."
The 970 will bring Macs into performance parity with PCs for ALL tasks, not just a few photoshop filters. There's simply no need to see Mac OS on x86. If that happened, Apple would end up like also-rans OS/2 and BeOS.
Originally posted by NETROMac
As you said, nothing new or remotely interesting, not to me at least. I added a few shots under that shows what kind of accelerating altivec can be capable of.
Thanks NETROMac.
Originally posted by Programmer
Audio and colour spaces are better represented by 64-bit floating point which 32-bit PowerPCs do just fine.
Well, not if you want performance.
In this case, I'm thinking more of the efficiency with which the 970 will do 64-bit FP than some notion that it's a new capability.
Originally posted by Amorph
Well, not if you want performance.
In this case, I'm thinking more of the efficiency with which the 970 will do 64-bit FP than some notion that it's a new capability.
With an AltiVec implementation the G4 will hold up okay. Depending on the size of your working set we may see little improvement with the 970 @ 1.4 GHz.
But yes, the 970's improvement will be very significant in doing scalar floating point work and anything memory bound.
Can't the Altivec unit do a double precision float? Or is it limited to single precision. Which Vue doesn't support?In fact, I always thought that the Altivec unit could be used as an extra fpu unit.
Sorry, not a clue what I'm talking about here. Paraphrasing and thrashing about wildly some talk I heard from the makers of Vue.
Personally, I know 3D performance could be improved on all platforms. Especially Apple towers.
Maybe somebody could clear up the Vue thing for me.
On those Macdoobie benches...even the low-end 1.4 970 humbles the the 'twice as fast'
I'm not a techie. (What, you can tell?) But those benches are still wowing me. That's another whole level for the Mac platform... I can see Alias adding to those 25% of customers being Mac.
Lemon Bon Bon
To answer your question about AltiVec
AltiVec can NOT do double precision
Is it a good enough answer?
AltiVec can NOT do double precision
Thanks for the confirmation Leonis.
So...why did Eon think it a problem? Doesn't it allow as accurate colour rendering? Do you get the odd pixel pop?Renders on a Mac always looked pretty good to me...
S'pose it don't matter if we're getting 970 fpu Hell Hounds!!!
Next dumb question...can the 970 do double precision?
Lemon Bon Bon
Originally posted by Lemon Bon Bon
Thanks for the confirmation Leonis.
So...why did Eon think it a problem? Doesn't it allow as accurate colour rendering? Do you get the odd pixel pop?Renders on a Mac always looked pretty good to me...
S'pose it don't matter if we're getting 970 fpu Hell Hounds!!!
Next dumb question...can the 970 do double precision?
OK, let's get this sorted out:
The G3 and G4 FPUs can do double-precision floating point. They just can't do it very quickly relative to other CPUs. (The G3 is particularly weak at FP at any precision).
The 970 FPU can do double-precision floating point, and it looks to be a significantly better performer than the G4 at this task.
AltiVec can indeed be used as an FPU, but only for single precision (32 bit) floating point. The G4 and the 970 both have dedicated scalar FPUs that can do both single and double precision work.
Double precision FP makes it easier to write rendering routines with a high degree of precision. AltiVec can't accelerate these routines, because it only works in single precision. (This is not to say that it isn't possible to write very accurate single precision renderers, only that hardly any of the commercial companies actually have. They lean on high-performing double-precision hardware instead.) The upshot of this is that if the 970 crunches double-precision floating point numbers significantly faster than the G4 - which has nothing to do with the fact that it's a 64 bit chip - then existing renderers will see a dramatic speedup.
As for 64 bit color, the video card doesn't have to know anything about 64-bit FP color, because the monitor it's driving certainly doesn't. The software could do all the work on the CPU, downsample to 24 bits, and the GPU would be none the wiser. However, if you want to be able to offload any color-dependent processing to the GPU (remember that transparency is a "color"), then it does have to be able to work with 64-bit FP color. No matter what, it'll end up spitting out 24-bit integer color, but the ability to work at a much higher precision and downsample for output will result in noticeably slicker, clearer rendering and compositing output.
The trend now, of course, is to get the GPU to do as much work as possible.
Originally posted by Amorph
John Carmack's been banging this drum for years now, and they listen to him.
I wonder why
Originally posted by Amorph
OK, let's get this sorted out:
A couple of points where I think there is potential confusion...
AltiVec can indeed be used as an FPU, but only for single precision (32 bit) floating point. The G4 and the 970 both have dedicated scalar FPUs that can do both single and double precision work.
AltiVec is a vector unit and can only be used for vector operations. Some of those possible operations are on vectors of 4 32-bit floats, but it cannot be used as a scalar floating point unit which is what the term "FPU" is usually refering to. This means to use AltiVec the developer must write vector code, and that is not a standardized process so the code is unique to PowerPC AltiVec processors. Scalar code, on the other hand, is built into C/C++ (and most other languages) and is cross-platform. Most floating point code out there is scalar in nature (i.e. it works on one number at a time) and therefore does not use the AltiVec unit.
There are some tools available to convert scalar code into vector code, but their use is not widespread and they are not tremendously effective.
Double precision FP makes it easier to write rendering routines with a high degree of precision. AltiVec can't accelerate these routines, because it only works in single precision. (This is not to say that it isn't possible to write very accurate single precision renderers, only that hardly any of the commercial companies actually have. They lean on high-performing double-precision hardware instead.) The upshot of this is that if the 970 crunches double-precision floating point numbers significantly faster than the G4 - which has nothing to do with the fact that it's a 64 bit chip - then existing renderers will see a dramatic speedup.
Keep in mind that there are more uses for numbers in rendering than just the pixels you end up seeing on the screen. The positions of the vertices, the texel coordinates for the texture, the normal on the vertex, the position of the camera, etc etc etc. The colours are actually a relatively small part of the whole process and in some ways are the least sensitive to precision requirements which is how GPUs have gotten away with relatively low precision on them (until recently).
Precision requirements usually come out of a long sequence of operations, or from places where really large and really small numbers are being combined. There are techniques available to mitigate these problems, but most developers don't bother to use them (or don't know about them). Floating point math is very often used without being fully understood. Sometimes, however, single precision just isn't enough. Sometimes even double precision isn't enough.
As for 64 bit color, the video card doesn't have to know anything about 64-bit FP color, because the monitor it's driving certainly doesn't. The software could do all the work on the CPU, downsample to 24 bits, and the GPU would be none the wiser. However, if you want to be able to offload any color-dependent processing to the GPU (remember that transparency is a "color"), then it does have to be able to work with 64-bit FP color. No matter what, it'll end up spitting out 24-bit integer color, but the ability to work at a much higher precision and downsample for output will result in noticeably slicker, clearer rendering and compositing output.
The need for high precision colour mainly comes from doing many blending and lighting passes, and the amount of that being done has been increasing dramatically as the hardware becomes more powerful. The modern GPUs which support floating point buffers (Radeon 9700 and later, geForceFX and later) can output full floating point precision, but cannot display it directly. To be displayed it has to be cut down to 8 or 10 bits per RGB channel. The loss of information in this conversion isn't too important, however, because no further blending will be done and the eye's preceptive limit is somewhere around 8-10 bits per channel. Alternatively the image can be read back from the card at full precision and used elsewhere.
The trend now, of course, is to get the GPU to do as much work as possible.
Radeon 9700 & later, geForceFX & later. They actually support 32-bit float per channel which is either 96-bit or 128-bit pixels depending on whether the alpha channel is supported/included.
Originally posted by Amorph
The 970 FPU can do double-precision floating point, and it looks to be a significantly better performer than the G4 at this task.
Just to amplify on this point (though I agree with Amorph's post).
1.0 GHz G4+ SpecFP 0187
1.8 GHz 970 SpecFP 1051
The 970's double precision floating point with be MUCH better.
Originally posted by Nevyn
Just to amplify on this point (though I agree with Amorph's post).
1.0 GHz G4+ SpecFP 0187
1.8 GHz 970 SpecFP 1051
The 970's double precision floating point with be MUCH better.
Looks like christmas is coming early this year
I guess that's why these guys will be buying Apple this year.
Guess the 970's going to be pret-ty good at 3D then.
I can see the power-starved Mac users baying like malnutritioned wolves at the WWDC...(Steve better be careful...) and outside those Apple retail stores... ((Picture of Apple store sales reps throwing the last dual 1.42 G4'e' carcass outside the store to rabid Mac heads. 'That's all we got...we can't make it go any faster...what do you want from us? Speed?' Incensed by the cpu impotence, the Mac-heads are after blood and proceed to savage the poor defenseless tower on the pavements outside...and after trashing the Ive Plastic MDD masterpiece then proceed to bang on the barricaded store doors...snarling and slabbering...'Jeee....ffiiiivvvvuh...')
Thanks to Amorph and Programmer and Co. for their full front assault on my sporadic questions.
Lemon Bon Bon
Originally posted by Lemon Bon Bon
I can see the power-starved Mac users baying like malnutritioned wolves at the WWDC...(Steve better be careful...) and outside those Apple retail stores... ((Picture of Apple store sales reps throwing the last dual 1.42 G4'e' carcass outside the store to rabid Mac heads. 'That's all we got...we can't make it go any faster...what do you want from us? Speed?' Incensed by the cpu impotence, the Mac-heads are after blood and proceed to savage the poor defenseless tower on the pavements outside...and after trashing the Ive Plastic MDD masterpiece then proceed to bang on the barricaded store doors...snarling and slabbering...'Jeee....ffiiiivvvvuh...')
The only thing that your forgot about was the pitchforks, torches, and somebody asking for a sacrifice.
This summer is going to be very sweet for the Mac Loyalists.
Mr. Lemon
To answer your question about AltiVec
AltiVec can NOT do double precision
Is it a good enough answer?
Nor would we want it to...
Amorph writes:
AltiVec can indeed be used as an FPU, but only for single precision (32 bit) floating point. The G4 and the 970 both have dedicated scalar FPUs that can do both single and double precision work.
Double precision FP makes it easier to write rendering routines with a high degree of precision. AltiVec can't accelerate these routines, because it only works in single precision. (This is not to say that it isn't possible to write very accurate single precision renderers, only that hardly any of the commercial companies actually have. They lean on high-performing double-precision hardware instead.) The upshot of this is that if the 970 crunches double-precision floating point numbers significantly faster than the G4 - which has nothing to do with the fact that it's a 64 bit chip - then existing renderers will see a dramatic speedup.
You gotta give them the whole skinny in layman's terms man ;-). You should have also mentioned that the reason why most all 3D render developers use double precision FP is because it covers up a lot of shoddy and sloppy algorithms.
Here is a link to a VERY knowledgeable programmer for PowerPCs. I've run it by Chris Cox from Adobe and a few other extremely sharp PPC programmers; They only confirmed that the person's reasoning is spot on.
Why we wouldn't want double-precision in the AltiVec unit (unless it was 256-bit) and: double precision is mainly used to cover up sloppy/shoddy algorithms.
It's the 19th or 20th post down on that page.
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Ed