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
Will Sony Deliver on 1080p?
Sony appears to have the most forward-looking set of outputs on the PlayStation 3, featuring two HDMI video outputs. There is no explicit support for DVI, but creating a HDMI-to-DVI adapter isn’t too hard to do. Microsoft has unfortunately only committed to offering component or VGA outputs for HD resolutions.
Support for 1080p will most likely be over HDMI, which will be an issue down the road. If you’re wondering whether or not there is a tangible image quality difference between 1080p and 720p, think about it this way - 1920 x 1080 looks better on a monitor than 1280 x 720, now imagine that blown up to a 36 - 60” HDTV - the difference will be noticeable.
At 720p, the G70 is entirely CPU bound in just about every game we’ve tested, so the RSX should have no problems running at 720p with 4X AA enabled, just like the 360’s Xenos GPU. At 1080p, the G70 is still CPU bound in a number of situations, so it is quite possible for RSX to actually run just fine at 1080p which should provide for some excellent image quality.
You must keep one thing in mind however; in order for the RSX to be CPU limited and not texture bandwidth limited at 1080p, the games it is running must be pixel shader bound.
For example, Doom 3 is able to run at 2048 x 1536 at almost 70fps on the 7800 GTX, however Battlefield 2 runs at less than 50 fps. Other games run at higher and lower frame rates; the fact of the matter is that the RSX won’t be able to guarantee 1080p at 60 fps in all games, but there should be some where it is possible. The question then becomes, as a developer, do you make things look great at 720p or do you make some sacrifices in order to offer 1080p support.
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.
Microsoft’s targets for the Xbox 360 are far more down to earth, with 720p and 4X AA being the requirements for all 360 titles. With a 720p target for all games, you can expect all Xbox 360 titles to render (internally) at 1280 x 720. We’ve already discussed that the 360’s GPU architecture will effectively give free 4X AA at this resolution, so there’s no reason not to have 4X AA enabled as well.
Most HDTVs will support either 1080i or 720p; those that natively support 720p will simply get a 720p output from the 360 with no additional signal processing. We’d be willing to bet that the game will still render internally at 720p and rely on either the Xbox 360’s TV encoder to scale the output to 1080i, or you can rely on your TV to handle the scaling for you. But for all discussion here, you can expect the Xbox 360 GPU to render games at 1280 x 720 with 4X AA enabled.
The support for 4X AA across the board is important, because on a large TV, even 720p is going to exhibit quite a bit of aliasing. But the lack of 1080p support is disturbing, especially considering it is a feature that Sony has been touting quite a bit. The first 1080p displays just hit the market this year, and the vast majority of the installed HDTV user base will only support 720p or 1080i, not 1080p. In the latter half of the Xbox 360 and PS3 life cycle, 1080p displays will be far more common place but it may be one more console generation before we get hardware that is capable of running all games at 1080p at a constant 60 fps.
In the end, Sony’s support for 1080p is realistic, but not for all games. For the first half of the console’s life, whether or not game developers enable AA will matter more than whether 1080p is supported. By the second half, it’s going to be tough to say.
Microsoft’s free 4X AA is wonderful and desperately needed, especially on larger TVs, but the lack of 1080p support is disappointing. It is a nice feature to have, even if only a handful of games can take advantage of it, simply because 1080p HDTV owners will always appreciate anything that can take full advantage of their displays. It’s not a make or break issue, simply because the majority of games for both platforms will still probably be rendered internally at 720p.
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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.