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Not Just A Compute Architecture

Nvidia’s GF100: Graphics Architecture Previewed, Still No Benchmarks
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Leading up to the GF100 launch, we’ve heard a lot of buzz about taking this opportunity to deemphasize its role in graphics in favor of GPU computing. Although representatives at Nvidia are the ones who first expressed concern over this “myth,” the company itself is really to blame for its spread.

The Fermi architecture was first introduced at Nvidia’s own GPU Technology Conference in late September of last year and, at the time, only details of the design’s compute capabilities were being discussed. While we had the whitepaper leaked to us prior to the embargo, such a disclosure literally one week after ATI’s Radeon HD 5870 launch was a bit much, since retail product was rumored to be more than a quarter away and AMD was already shipping the world’s first DirectX 11 hardware. Nevertheless, we read with great interest some of the most detailed overviews of the Fermi architecture’s capabilities.

Of course, now Nvidia wants everyone to know that it hasn’t backed down from a dedication to graphics performance, either. The GPC architecture, emphasis on geometry, and full DirectX 11 compliance all support such an assertion. However, it’s still easy to look at GF100 and see where the company sought balance between compute and graphics, from clear nods to double precision floating-point math to the chip’s cache architecture.

Each of the 16 SMs sports its own 64KB shared memory/L1 cache pool, which can either be configured as 16KB shared memory/48KB L1 or vice versa. GT200 included 16KB of shared memory per SM to keep data as local as possible, minimizing the need to go out to frame buffer for information. But by expanding this memory pool and making it almost-dynamically configurable, Nvidia addresses graphics and compute problems at the same time. In a physics- or ray-tracing-based compute scenario, for example, you don’t have a predictable addressing mechanism, so the small shared space/large L1 helps improve memory access. This’ll become particularly notable once game developers start taking better advantage of DirectCompute from within their titles.


GT200
GF100
Benefits
L1 Texture Cache (Per Quad)
12KB
12KB
Texture filtering
Dedicated L1 Load/Store Cache
None
16/48KB
Useful in physics/ray-tracing
Total Shared Memory
16KB
16/48KB
More data reuse among threads
L2 Cache
256KB (texture read only)
768KB (all clients read/write)
Compute performance, texture coverage


From there you have a 768KB L2, which is significantly larger and more functional than GT200’s 256KB texture read-only cache. Because it’s unified, GF100’s L2 replaces the L2 texture cache, ROP cache, and on-chip FIFOs, as any client can read from it or write to it. This is another area where compute performance is clearly the target in Nvidia’s crosshair. However, gaming performance should see a benefit as well since SMs working on the same data will make fewer trips to memory.

It’s entirely true that GF100 represents a massive step forward in what third-party developers can do with the compute side. But it’s bolstered by the fact that DirectCompute and OpenCL are here, that AMD supports both APIs as well, and that the way we’re going to get more realistic games is through developers enabling GPU computing within their titles. Ray tracing (either used alone or with rasterization), voxel rendering, custom depth of field kernels, particle hydrodynamics, and AI path-finding are all potential applications of what we might see by virtue of compute-enabled hardware.

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  • 26 Hide
    decembermouse , January 18, 2010 3:34 AM
    I feel like you left some info out, whether you just never read it or didn't mention it for fear of casting doubts on GF100... I've heard (and this isn't proven) that they had to remove some shaders and weren't able to reach their target clocks even with this revision (heard the last one didn't cut the mustard which is why they're hurrying the new one along and why we have to wait till March). Also, be careful about sounding too partisan with Nvidia before we have more concrete info on this.

    And yes, it does matter that AMD got DX11 hardware out the gate first. Somehow, when Nvidia wins at something, whether that's being first with a technology, having the fastest card on the market, or a neato feature like Physx, it's a huge deal, but when AMD has a win, it's 'calm down people, let's not get excited, it's no big deal.' The market and public opinion, and I believe even worth of the company have all been significantly boosted by their DX11 hardware. It is a big deal. And it'll be a big deal when GF100 is faster than the 5970 too, but they are late. I believe it'll be April before we'll realistically be able to buy these without having to F5 Newegg every 10 seconds for a week, and in these months that AMD has been the only DX11 player, well, a lot of people don't want to wait that long for what might be the next best thing... all I'm trying to say is let's try not to spin things so one company sounds better. It makes me sad when I see fanboyism, whether for AMD, Intel, Nvidia, whoever, on such a high-profile review site.
  • 25 Hide
    cangelini , January 18, 2010 3:44 AM
    dingumfOh look, no benchmarks.


    *Specifically* mentioned in the title of the story, just to avoid that comment =)
  • 24 Hide
    randomizer , January 18, 2010 3:05 AM
    GF100 is entering the ranks of Duke Nukem Forever. We keep seeing little glimpses but the real thing might as well not exist.
Other Comments
  • 24 Hide
    randomizer , January 18, 2010 3:05 AM
    GF100 is entering the ranks of Duke Nukem Forever. We keep seeing little glimpses but the real thing might as well not exist.
  • 23 Hide
    duckmanx88 , January 18, 2010 3:29 AM
    dingumfOh look, no benchmarks.


    wth is he supposed to benchmark? nothing has been released it's just an article giving us details on what we can expect within the next two months.
  • 26 Hide
    decembermouse , January 18, 2010 3:34 AM
    I feel like you left some info out, whether you just never read it or didn't mention it for fear of casting doubts on GF100... I've heard (and this isn't proven) that they had to remove some shaders and weren't able to reach their target clocks even with this revision (heard the last one didn't cut the mustard which is why they're hurrying the new one along and why we have to wait till March). Also, be careful about sounding too partisan with Nvidia before we have more concrete info on this.

    And yes, it does matter that AMD got DX11 hardware out the gate first. Somehow, when Nvidia wins at something, whether that's being first with a technology, having the fastest card on the market, or a neato feature like Physx, it's a huge deal, but when AMD has a win, it's 'calm down people, let's not get excited, it's no big deal.' The market and public opinion, and I believe even worth of the company have all been significantly boosted by their DX11 hardware. It is a big deal. And it'll be a big deal when GF100 is faster than the 5970 too, but they are late. I believe it'll be April before we'll realistically be able to buy these without having to F5 Newegg every 10 seconds for a week, and in these months that AMD has been the only DX11 player, well, a lot of people don't want to wait that long for what might be the next best thing... all I'm trying to say is let's try not to spin things so one company sounds better. It makes me sad when I see fanboyism, whether for AMD, Intel, Nvidia, whoever, on such a high-profile review site.
  • 8 Hide
    megamanx00 , January 18, 2010 3:37 AM
    Well, not much new here. I wouldn't really be surprised if the 2x performance increase over the GTX285 was a reality. Still, the question is if this new card will be able to maintain as sizable a performance lead in DX11 games when Developers have been working with ATI hardware. If this GPU is as expensive to produce as rumored will nVidia be able to cope with an AMD price drop to counter them?

    I hope that 5850s on shorter PCBs come out around the time of the GF100 so they can drop to a price where I can afford to buy one ^_^
  • 25 Hide
    cangelini , January 18, 2010 3:44 AM
    dingumfOh look, no benchmarks.


    *Specifically* mentioned in the title of the story, just to avoid that comment =)
  • 20 Hide
    randomizer , January 18, 2010 4:10 AM
    cangelini*Specifically* mentioned in the title of the story, just to avoid that comment =)

    You just can't win :lol: 
  • -5 Hide
    sabot00 , January 18, 2010 4:14 AM
    Finally some solid info on GF100.
  • 5 Hide
    tacoslave , January 18, 2010 4:27 AM
    Even though im a RED fan im excited because its a win win for me either way. If amd wins than im proud of them but if nvidia wins than that means price drops!!! And since they usually charge more than ati for a little performance increase than ill probably get a 5970 for 500 or less (hopefully). Anyone remember the gtx280 launch?
  • 7 Hide
    Reynod , January 18, 2010 5:07 AM
    Chris your review was unusually kind.

    I'd rank it up there with Anand's on the first Phenom iteration - he had ES well before the others and there was mounting pressure to at least publish something ... and the AMD fanbois should consider tha article very fair.

    I had heard Nvidia were booting some silicon and the clocks were low ... and in order to get within the power elvelope it was likely some SP's would have to be shaved ... that's about all anyone can say.

    I imagine NVidia will also be concentrating on ensuring the die is securely attached to the substrate.

    They won't want to cheese off the OEM's like last time:

    http://www.theinquirer.net/inquirer/news/1050052/nvidia-chips-underfill
  • 5 Hide
    falchard , January 18, 2010 5:13 AM
    One thing I wonder is if nVidia finally pushes forward with this architecture, does this mean developers will finally start utilizing some of the tech ATI has had in its cards for generations? For instance, will they utilize more efficient poly rendering effectively making ATI cards perform 300% faster in drawing polies and make every consumer nVidia card before the GF100 moot?

    Also will they adopt a naming convention that finally makes sense? Up to 9000, reset, skip double digits and 100, go straight to 200. Now go back to 100. I mean seriously who comes up with these names?
    G80, G92, G200, GF100..
  • 12 Hide
    Kelavarus , January 18, 2010 5:27 AM
    One thing you didn't mention about the Supersonic Sled Tech Demo there is that it took three GF100s in a triple-SLI configuration to do that.
  • 2 Hide
    TheGreatGrapeApe , January 18, 2010 5:28 AM
    Chris, some 'leaked' 'internal' nV slides recently appeared with THG results from the HD5970 review, since I can't ask the question I would like yo about that (there's no way you could answer if true), I'll simply ask, were you aware of this?

    http://news.softpedia.com/newsImage/Alleged-GeForce-GTX-360-and-380-benchmarks-Surface-3.jpg/

    Slight tweaking of the RE:5 results (likely because they didn't point in the right direction for the existing cards) :evil: 

    And Charlie's recent 'Pro-nVidia' article is somewhat telling about the possibility of scaling downward, what's your opinion on it if you can say, other than "Charlie's just being Charlie". ;) 

    http://www.semiaccurate.com/2010/01/17/nvidia-gf100-takes-280w-and-unmanufacturable
  • 1 Hide
    aggrressor , January 18, 2010 5:31 AM
    umm, Guys, If you want benches - They are "kind of" available at guru3d. I have just read their article, and while it's a bit too technical for my taste, they've recorded a Far Cry 2 bench at Nvidia conference on a crappy camera. The end result was 50 FPS on GTX285 vs 84 FPS on GF100 based product. Now I know it's not raw numbers or charts or anything like that, but at least that gives me a rough idea of what GT300 stuff will be like.
  • 7 Hide
    randomizer , January 18, 2010 5:32 AM
    dingumfThis is the end of the NDA. Do you even know what NDA is kid?

    Do you? The end of an NDA does not mean every detail has to be divulged. You can still only provide the details that have been given to you. If NVIDIA don't hand out the review samples, you can't benchmark them. It's not rocket science!
  • 2 Hide
    masterjaw , January 18, 2010 5:33 AM
    How long should we wait before we actually see an article like "Alas! Fermi has arrived (late?)".

    If they claim that it is "significantly faster" then better it would be or else..
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