Microsoft's Xbox 360, Sony's PS3 - A Hardware Discussion
by Anand Lal Shimpi & Derek Wilson on June 24, 2005 4:05 AM EST- Posted in
- GPUs
The Consoles and their CPUs
The CPUs at the heart of these two consoles are very different in architecture approach, despite sharing some common parts. The Xbox 360’s CPU, codenamed Xenon, takes a general purpose approach to microprocessor design and implements three general purpose PowerPC cores, meaning they can execute any type of code and will do it relatively well.
The PlayStation 3’s CPU, the Cell processor, pairs a general purpose PowerPC Processing Element (PPE, very similar to one core from Xenon) with 7 working Synergistic Processing Elements (SPEs) that are more specialized hardware designed to execute certain types of code.
So the comparison between Xenon and Cell really boils down to a comparison between a general purpose microprocessor, and a hybrid of general purpose and specialized hardware.
Despite what many have said, there is support for Sony’s approach with Cell. We have discussed, in great detail, the architecture of the Cell processor already but there is industry support for a general purpose + specialized hardware CPU design. Take note of the following slide from Intel’s Platform 2015 vision for their CPUs by the year 2015:
The use of one or two large general purpose cores combined with specialized hardware and multiple other smaller cores is in Intel’s roadmap for the future, despite their harsh criticism of the Cell processor. The difference is that Cell appears to be far too early for its time. By 2015 CPUs may be manufactured on as small as a 32nm process, significantly smaller than today’s 90nm process, meaning that a lot more hardware can be packed into the same amount of space. In going with a very forward-looking design, the Cell processor architects inevitably had to make sacrifices to deal with the fact that the chip they wanted to design is years ahead of its time for use in general computation.
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BenSkywalker - Sunday, June 26, 2005 - link
""One thing is for sure, support for two 1080p outputs in spanning mode (3840 x 1080) on the PS3 is highly unrealistic. At that resolution, the RSX would be required to render over 4 megapixels per frame, without a seriously computation bound game it’s just not going to happen at 60 fps." -- Quote from page 10"First off 1080p doesn't support 60FPS as of this moment anyway, and there are an awful lot of games on consoles that aren't remotely close to being GPU bound anyway. Remember that the XBox has titles now that are pushing out 1080i and the RSX is easily far more then four times the speed of the GPU in the XBox.
tipoo - Wednesday, August 6, 2014 - link
"RSX is easily far more then four times the speed of the GPU in the XBox."It's funny reading these comments years later, and seeing how crazy the PS3 hype machine was. I assume this insane comment reffered to the 1 terraflop RSX thing, which was a massive joke. RSX was worse than Xenon not only in raw gflops (180 vs over 200 I think), but since it didn't have unified shaders it could be bottlenecked by a scene having too much vertex or pixel effects and leaving shaders underused.
calimero - Sunday, June 26, 2005 - link
Here is one tip about Cell:to play MP3 files (stereo) on PC you need 100MHz 486 CPU. Atari Falcon030 with MC68030 (16MHz) and DSP (32MHz) can do same thing!
Everyone who know to program will find Cell outstanding and thrilling everyone else who pretend to be a programer please continue to waste CPU cycles with your shity code!
coolme - Sunday, June 26, 2005 - link
"Supporting 1080p x2 may seem like overkill,"It's not gonna support 1080p x2
"One thing is for sure, support for two 1080p outputs in spanning mode (3840 x 1080) on the PS3 is highly unrealistic. At that resolution, the RSX would be required to render over 4 megapixels per frame, without a seriously computation bound game it’s just not going to happen at 60 fps." -- Quote from page 10
nevermind4711 - Sunday, June 26, 2005 - link
People have different ways of expressing the frequency of DDRAM. The correct memory frequency of 7800GTX is 256MB/256-bit GDDR3 at 600MHz, but as it is double rate some people say 1200 MHz.In the same way you can say the RSX memory is operating at 1400 MHz. How else could 128 bit result in a memory bandwidth of 22 GB/s for the RTX?
#64 knitecrow, who is your source that the RSX does not contain e-dram, or is it just speculation?
Besides, your conclusion from extrapolating the transistor count may be correct, but assuming the transistor count is proportional to the number of pixel pipelines is a rather big simplification, there is quite a lot of other stuff inside a GPU as well, stuff that does not scale proportionally to the pixel pipelines.
Furen - Sunday, June 26, 2005 - link
The RSX is supposed to be clocked higher but will only have a 700MHz, 128bit memory bus (as opposed to the 1200MHz, 256bit memory bus on the 7800gtx).knitecrow - Saturday, June 25, 2005 - link
#61too bad you don't speak marketing.
When they say near.. it means very close. Could be slightly under or over. If it was something like 320M... they will be hyp3ing 320M.
#62 too bad you are wrong
with 300M transistors, the RSX is a native 24 pixel pipeline card
You can extrapolate the number by looking at:
6800ultra - 16 - 222M
6600GT - 8 - 144M
it has no eDRAM.
The features remain to be seen, but its going to be a G70 derivate -- just like XGPU for the xbox was a geforce3 derivative.
There is absolutely no evidence to suggest that the RSX is going to be more powerful than 7800GTX.
Just because a product comes out later doesn't make it better
Exhibit A:
Radeon 9700pro vs. 5800ultra
Darkon - Saturday, June 25, 2005 - link
http://www.psinext.com/index.php?categoryid=3&...Dukemaster - Saturday, June 25, 2005 - link
I think it is very clear why the RSX gpu has the same number of transistors but still is more powerfull then the 7800GTX: the 7800GTX is a chip with 32 pipelines with 8 of them turned off.nevermind4711 - Saturday, June 25, 2005 - link
Interesting article. However, I find it strange that Anand and Derek do not comment on the difference in floating point capacity between the combatants. 1 TFlops for X360 vs. 2 TFlops for PS3. For X360 we know that the majority of flops come from the GPU, where probably the big part consists of massively paralell compare ops and such coming from the AA- and filtering circuitry integrated with the e-DRAM.It would be very interesting to know how the RSX provides 1.8 TFlops. I do not think the G70 has a capacity anything near that. Could it be possible that Sony will bring some e-DRAM to the party together with AA and filtering circuitry similar to X360. After all Sony has quite some experience of e-DRAM from PS2 and PSP.
Anand and Derek wrote "Both the G70 and the RSX share the same estimated transistor count, of approximately 300.4 million transistors." Where do this information come from? Sony only said in its presentation the RSX will have 300+ mil t:s. G70 we now know contains 302 mil t:s.
#48: Sony may very well have replaced some video en/de-coding circuitry of the G70 with some e-dram circuitry.