NVIDIA's GeForce 8800 (G80): GPUs Re-architected for DirectX 10
by Anand Lal Shimpi & Derek Wilson on November 8, 2006 6:01 PM EST- Posted in
- GPUs
General Purpose Processing
With all the talk about how general purpose G80 is, can we expect it to replace our shiny new quad core desktop processor? This isn't quite possible at this point due to the way most general purpose code uses the CPU. Many dependencies and low parallelism prevent NVIDIA from simply dropping this in a motherboard and running Windows on it.
But there are general purpose tasks that lend themselves well to the parallelism of G80, and NVIDIA is enabling developers to take advantage of this via a technology they call CUDA (Compute Unified Device Architecture).
The major thing to take away from this is that NVIDIA will have a C compiler that is able to generate code targeted at their architecture. We aren't talking about some OpenGL code manipulated to use graphics hardware for math. This will be C code written like a developer would write C.
A programmer will be able to treat G80 like a hugely parallel data processing engine. Applications that require massively parallel compute power will see huge speed up when running on G80 as compared to the CPU. This includes financial analysis, matrix manipulation, physics processing, and all manner of scientific computations.
NVIDIA has written a totally separate driver for G80 that will be used to run compiled C code targeted at G80. The reason they've done this is because the usage model for GPGPU programming is so different from that of graphics. Both the graphics driver and the CUDA driver can be running on G80 at the same time. This may allow programmers to take advantage of CUDA for in game physics on a single card. The driver changes the conceptual layout of the GPU into something that looks more like this:
This design, along with stream output capabilities, allows programmers to treat the GPU like a general purpose data processing engine. Each block of 16 SPs is able to share data with each other and can perform multiple passes on the data without having to write out and read back in from the onboard graphics memory. Developers are given the ability to manage the caches themselves.
Will NVIDIA make an x86 CPU? Most likely not, but we may see NVIDIA produce even more general purpose CPUs for the handheld, CE, integrated markets. NVIDIA may end up becoming a producer of system on a chip solutions utilizing its graphics technology and simply expanding G80 to be more general purpose (and obviously get rid of some of the SPs in order to lower costs).
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JarredWalton - Wednesday, November 8, 2006 - link
The text is basically complete, and minor spelling issues aren't going to change the results. Obviously, proofing 29 pages of article content is going to take some time. We felt our readers would be a lot more interested in getting the content now rather than waiting even longer for me to proof everything. I know the vast majority of readers don't bother to comment on spelling and grammar issues, but my post was to avoid the comments section turning into a bunch of short posts complaining about errors that will be corrected shortly. :)Iger - Wednesday, November 8, 2006 - link
Pff, of course we would! If I would like to read a novel I would find a book! Results first - proofing later... if ever :) Thanks for the article!JarredWalton - Wednesday, November 8, 2006 - link
Did I say an hour? Okay, how about I just post here when I'm done reading/editing? :)JarredWalton - Wednesday, November 8, 2006 - link
Okay, I'm done proofing/editing. If you still see errors, feel free to complain. Like I said, though, try to keep them in this thread.--Jarred
LuxFestinus - Thursday, November 9, 2006 - link
Pg. 3 under <b>Unified Shaders</b>Should read as follows:
<i>Until now, building a GPU with unified shaders would not have <b>been</b> desirable, let alone practical, but Shader Model 4.0 lends itself well to this approach.</i>
Good try though.;)
shabby - Wednesday, November 8, 2006 - link
$600 for the gtx and $450 for the gts is pretty good seeing how much they crammed into the gpu, makes you wonder why the previous gen topped 650 bucks at times.dcalfine - Wednesday, November 8, 2006 - link
How does the 8800GTX compare to the 7950GX2? Not just in FPS, but also in performance/watt?dcalfine - Wednesday, November 8, 2006 - link
Ignore ^^^sorry
Hot card by the way!
neogodless - Wednesday, November 8, 2006 - link
I know you touched on this, but I assume that DirectX 10 is still not available for your testing platform, Windows XP Professional SP2, and additionally no games have been released for that platform. Is this correct? If so...Will DirectX 10 be made available for Windows XP?
Will you publish a new review once Vista, DirectX 10 and the new games are available?
Can we peak into the future at all now?
JarredWalton - Wednesday, November 8, 2006 - link
DX10 will be Vista only according to Microsoft. What that means according to some game developers is that DX10 support is going to be somewhat slow, and it's also going to be a major headache because for the next 3-4 years they will pretty much be required to have a DX9 rendering solution along with DX10.