360 GPU and a boatload of other acronyms

A good discussion about the future of the 360 and it’s ability to render some of today’s newest graphics. The discussion started around the ability to render the scenes displayed in EA and Crytek’s newest demo called Crysis displayed at GDC.

Acert93

Xenos is not a miracle chip. What it is, though, is a chip designed "smartly". There is really little point to continue increasing the TMUs. Sure, it helps in "Super DX9" games, which are really just DX7 games with some shaders tossed on top. News Flash: Oblivion was the FIRST game to require SM2.0. Yeah, scary. It is a 4 year old API and we are just NOW seeing games require it.

Where Xenos excells is in shaders, specifically SM3.0 (plus the extra stuff it can do beyond that spec). How many PC games use SM3.0? FEAR, SC:CT, Far Cry, Oblivion... uhhh.... maybe a couple others. How many build around it? 0. All these games are DX9 games with an added path for some "extra goodies". And we wont be seeing any SM3.0 heavy games any time soon... maybe never. Why? Because while Nvidia owns 88% of all SM3.0 GPUs, their SM3.0 performance SUCKS. It is 1/4th the speed of the comparable X1000 series GPUs in heavy dynamic branching.

The issue is a paradigm one. Xenos IS NOT A PC CHIP. It was designed for the consoles and is much more future looking. Sure, a couple games have used HDR+AA, and most now have 4xAA. But by all developer accounts they are hardly touching the Shader ALUs. None have used the hardware tesselation or HOS. Until recently developers were stuck using the manual tiling and could not use XPC. A number of titles, mostly ports of Xbox engines or PC games, could not use the eDRAM because they did not do an early Z-pass which made them incompatible with the eDRAM tiling.

But as much as we can knock the 360 in areas (I had a post this weekend outlining all the issues MS has had and continues to have), some of you PC fanboys are waaaay too biased. Look at something as simple as Kameo or PGR3. No racer on the PC gets close to PGR3. Further, Kameo has over 1M particle physics-effects on screen at a time without slow down. You CANNOT do that on a current PC--the 360 chewed through it. And some filtering issues aside, CoD2 runs very, very well on the 360. Much better than a $300 GPU.

There will be games designed for the 360 from day 1. The new PGR, Forza, Halo, etc. These titles will use the eDRAM correctly and move the work load away from the TMUs to the Shaders. Those who are judging the software by the early PC/Xbox ports can dance all you want, but this is no different than when the PS2 got a lot of PS1 ports or when the Xbox got a number of PS2 ports. Its not like the Xbox 360 has not provided high-end PC graphics on a cheap console--because it has.

Obviously the 360 wont be the best hardware on the market. The X1900 already has more raw PS power; the R600 will have Geometry Shaders, more shader performance across the board, more effecient shading model, and resolve a number of issues Xenos has. Of course the 360 has eDRAM and 100% speed HDR which resolves a number of pipeline stalls, and it is a closed box with a very close symbiotic relationship with the CPU that has 2-4x as much realworld vector performance per core over an x86 chip.

Ultimately we are seeing the "dead end" of the DX7 approach. DX8 and DX9 just added more robust shader models, but ultimately DX was designed with progrability as an extra feature--not the core. Further, the hardware and engines were designed with a 1:1 TMU:Shader arrangement. I can count DOZENS of games where the X1900XT is less than 5% faster than the X1800XT. The X1900XT has 3x the peak shader performance, so why no improvement? Because the games are NOT suited for the extra shader power.

Toss in all the features the Xbox 360 has and you can make some really great software. But basing its performance off of SM2.0 games designed with PC (or Xbox!) hardware paradigms in mind is really foolish. The PC is a great format for those who have the money. But reality is that PCs are expensive and get fewer games and even fewer exclusives. For those of us who like mods, Mice, and like spending crazy money it is a great platform. But the "PC is always better" arguement is pretty much wrong.

GrimThorne

Yes Acert. It is the end of the "screenshots" era. We will no longer be able to determine the visual fidelity of games through frozen game footage or target video. It simply no longer measures up to the quality displayed in full motion game footage.

Acert it seems to me that many are not taking into consideration that Crytek2 wasn't even designed around the final build of DX10.

MSDN subscribers who have already been downloading betas of Longhorn/DX10/Vista have already stated that the 360's Xenos GPU already surpasses the criteria for WGF2.0 - WGF2.2+. These were earlier builds of DX10. But that's only the half of it. The Xenos natively supports a number of advances that the X1900 and DX10 itself does not support natively.

For example, DX10 at this time(as far as we know) does not natively support physics, hair, water and clothing. The Xenos supports all of these natively and a host of post processing features which it is capable of rendering in just one texture pass.

The Xenos will even support Geometry Shaders. That's right, the Xenos can generate geometry. While this feature is not done natively, it is accomplished through the Xenos' innovative MEMEXPORT function. By slaving one the three Xbox 360's Cores through the Xenos' MEMEXPORT function, the Xenos can create geometry.

BTW, the Xenos' MEMEXPORT function is another advance that the X1900 doesn't have. I would be very surprised that whatever hardware Crytek used to demonstrate the Crysis engine has the Xenos' MEMEXPORT function or one texture pass multi-post processing features. No current hardware or vaporware has the Xenos' specs.

The only snag I would see is soft shadows. Despite what the misinformed have been saying around here, the 360 can indeed do soft shadows. The problem is that the Xenos is no different than any other gaming hardware with soft shadows turned on. Games will take performance hits when soft shadows are applied. Crysis could run at a respectable frame rate with soft shadows applied if Crytek developed for the 360's hardware and not just provide a lazy coded port.

If Crysis becomes a port, then Xbox360 version will probably suffer. If Crytek develops a seperate version to play to the strengths of the Xenos then it's possible to make the game even better than the PC version would be.

There is so much to the Xenos, but developers have to be willing to exploit the hardware and develop exclusively for it.