Applications of GF100’s Compute Hardware

Last but certainly not least are the changes to gaming afforded by the improved compute/shader hardware. NVIDIA believes that by announcing the compute abilities so far ahead of the gaming abilities of the GF100, that potential customers have gotten the wrong idea about NVIDIA’s direction. Certainly they’re increasing their focus on the GPGPU market, but as they’re trying their hardest to point out, most of that compute hardware has a use in gaming too.

Much of this is straightforward: all of the compute hardware is what processes the pixel and vertex shader commands, so the additional CUDA cores in the GF100 give it much more shader power than the GT200. We also have DirectCompute, which can use the compute hardware to quickly do some things that couldn’t be done quickly via shader code, such as Self Shadowing Ambient Occlusion in games like Battleforge, or to take an NVIDIA example, the depth-of-field effect in Metro 2033.

Perhaps the single biggest improvement for gaming that comes from NVIDIA’s changes to the compute hardware are the benefits afforded to compute-like tasks for gaming. PhysX plays a big part here, as along with DirectCompute it’s going to be one of the biggest uses of compute abilities when it comes to gaming.

NVIDIA is heavily promoting the idea that GF100’s concurrent kernels and fast context switching abilities are going to be of significant benefit here. With concurrent kernels, different PhysX simulations can start without waiting for other SMs to complete the previous simulation. With fast context switching, the GPU can switch from rendering to PhysX and back again while wasting less time on the context switch itself. The result is that there’s going to be less overhead in using the compute abilities of GF100 during gaming, be it for PhysX, Bullet Physics, or DirectCompute.

NVIDIA is big on pushing specific examples here in order to entice developers in to using these abilities, and a number of demo programs will be released along with GF100 cards to showcase these abilities. Most interesting among these is a ray tracing demo that NVIDIA is showing off. Ray tracing is something even G80 could do (albeit slowly) but we find this an interesting way for NVIDIA to go since promoting ray tracing puts them in direct competition with Intel, who has been showing off ray tracing demos running on CPUs for years. Ray tracing nullifies NVIDIA’s experience in rasterization, so to promote its use is one of the riskier things they can do in the long-term.


NVIDIA's car ray tracing demo

At any rate, the demo program they are showing off is a hybrid program that showcases the use of both rasterization and ray tracing for rendering a car. As we already know from the original Fermi introduction, GF100 is supposed to be much faster than GT200 at ray tracing, thanks in large part due to the L1 cache architecture of GF100. The demo we saw of a GF100 card next to a GT200 card had the GF100 card performing roughly 3x as well as the GT200 card. This specific demo still runs at less than a frame per second (0.63 on the GF100 card) so it’s by no means true real-time ray tracing, but it’s getting faster all the time. For lower quality ray tracing, certainly this would be doable in real-time.


Dark Void's turbulence in action

NVIDIA is also showing off several other demos of compute for gaming, including a PhysX fluid simulation, the new PhysX APEX turbulence effect on Dark Void, and an AI path finding simulation that we did not have a chance to see. Ultimately PhysX is still NVIDIA’s bigger carrot for consumers, while the rest of this is to entice developers to make use of the compute hardware through whatever means they’d like (PhysX, OpenCL, DirectCompute). Outside of PhysX, heavy use of the GPU compute abilities is still going to be some time off.

Better Image Quality: CSAA & TMAA 3D Vision Surround: NVIDIA’s Eyefinity
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  • marc1000 - Tuesday, January 19, 2010 - link

    hey, Banshee was fine! I had one because by that time the 3dfx api was better than DirectX. But suddenly everything became DX compatible and that was one thing 3dfx GPUs could not do... then I replaced that Banshee with a Radeon 9200, later a Radeon X300 (or something), then Radeon 3850, and now Radeon 5770. I'm always in for the mainstream, not the top of the line, and Nvidia is not paying enough atention to mainstream since Geforce FX series...
  • Zool - Monday, January 18, 2010 - link

    The question is when they will come with mid range variants. The GF100 seems to be 448SP variant and the 512SP card will be only after A4 revision or who knows.
    http://www.semiconductor.net/article/438968-Nvidia...">http://www.semiconductor.net/article/43...en_Calls...
    The interesting part on the article is the graph which shows the exponecial increase in leakage power after 40nm and less. (which of course hurts more if u have a big chip and diferent clocks to maintain)
    They will have even more problems now that dx11 cards will be only gt300 architecture so no rebrand choices for mid range and lower.
    For consumer gf100 will be great if they can buy it somewhere in the future, but nvidia will bleed more on it than the GT200.
  • QChronoD - Monday, January 18, 2010 - link

    Maybe I'm missing something, but it seems like PC gaming has lost most of its value in the last few years. I know that you can run games at higher resolutions and probably faster framerates than you can on consoles, but it will end up costing more than all 3 consoles combined to do so. It just seems to have gotten too expensive for the marginal performance advantage.

    That being said, I bet that one of these would really crank through Collatz or GPUGRID.
  • GourdFreeMan - Monday, January 18, 2010 - link

    I certainly share that sentiment. The last major graphical showcase we had was Crysis in 2007. There have been nice looking PC exclusive titles (Crysis Warhead, Arma 2, the Stalker franchise) since then, but no significant new IP with new rendering engines to take advantage of new technology.

    If software publishers want our money, they are going to have to do better. Without significant GPGPU applications for the mainstream consumer, GPU manufacturers will eventually suffer as well.
  • dukeariochofchaos - Monday, January 18, 2010 - link

    no, i think you're totally correct, from a certain point of view.

    i had the thought that the DX9 support is probably more than enough for console games, and why would developers pump money into DX11 support for a product that generates most of it's profits on consoles?

    obviously, there is some money to be made in the pc game sphere, but is it really enough to drive game developers to sink money into extra quality just for us?

    At least NV has made a product that can be marketed now, and into the future, for design/enterprise solutions. That should help them extract more of the value out of their r&d if there are very few DX11 games for the lifespan of fermi.



  • Calin - Monday, January 18, 2010 - link

    If Fermi is working good, NVidia is in a great place for the development of their next GPU - they'll only need to update some things here and there, based mostly on where the card's performance lack (improve this, improve that, reduce this, reduce that). Also, they are in a very good place for making lower-end cards based on Fermi (cut everything in two or four, no need to redesign the previously fixed function blocks).

    As for AMD... their current design is in the works and probably too advanced for big changes, so their real Fermi-killer won't come faster than a year or so (that is, if Fermi proves to be so great a success as NVidia wants it to be).
  • toyota - Monday, January 18, 2010 - link

    what I have saved on games this year has more than paid for the difference between the price of a console and my pc.
  • Stas - Tuesday, January 19, 2010 - link

    that ^^^^^^^
    besides, with Steam/D2D/Impulse there is new breath in PC gaming. constant sales on great games, automatic updates, active support, forums full of people, all integrated with virtual community (profiles, chats, etc.). a place to release demos, trailers, etc. I was worried about PC gaming 2-3 years ago, but I'm absolutely confident that it's coming back better than ever.
  • deeceefar2 - Monday, January 18, 2010 - link

    Are the screen shots from left 4 dead 2 missing at the end of page 5?

    [quote]
    As a consequence of this change, TMAA’s tendency to have fake geometry on billboards pop in and out of existence is also solved. Here we have a set of screenshots from Left 4 Dead 2 showcasing this in action. The GF100 with TMAA generates softer edges on the vertical bars in this picture, which is what stops the popping from the GT200.
    [/quote]
  • Ryan Smith - Monday, January 18, 2010 - link

    Whoops. Fixed.

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