AMD's "Small-Die" Strategy

We outlined AMD's "new" GPU strategy in our Radeon HD 4850 preview article, but in short AMD has committed to designing GPUs for the mainstream $199 - $299 segment and simply using CrossFire (multi-GPU) to address higher end markets. NVIDIA on the other hand will continue to make very large monolithic GPUs in order to continue to push the industry forward. Both approaches are appreciated and necessary, they simply target different markets.

In our GT200 review we highlighted the fact that NVIDIA had built an extremely large, highly parallel, microprocessor. With 1.4 billion transistors and a die size of around 576 mm^2, NVIDIA's GT200 is nothing short of huge.

The table on the previous page shows that AMD's RV770, despite being aimed at mainstream gamer price points ($199 - $299), is also very large. At 956M transistors, the RV770 has 44% more transistors than RV670 and 68% the transistor count of NVIDIA's GT200. We threw the RV770 into NVIDIA's die size comparison just for kicks:


Based on what we know of NVIDIA's die size, this should be to scale

Even AMD's die, although designed to be svelte and affordable, is big - especially for being fabbed at TSMC. NVIDIA still holds the crown for largest die fabbed at TSMC, but AMD shows us that even a more mainstream approach still requires tons of transistors. As we mentioned in our 4850 preview:

"A pair of RV770s, AMD's new GPU, end up consuming more power than a single GT200 - despite being built on a smaller 55nm process.

A pair of these RV770s only costs $400 compared to $650 for a single GT200, but I suspect that part of that is due to differences in manufacturing process. If NVIDIA hadn't been so risk averse with the GT200 and built it on 55nm (not that I'm advocating it, simply posing a hypothetical), the cost differences would be smaller - if not in favor of NVIDIA since GT200 is built on a single card.

When the smoke clears, AMD's strategy is to simply build a GPU for the masses and attempt to scale it up and down. While NVIDIA is still building its GPUs the same way it has for decades, starting very large and scaling down.

AMD isn't taking a radically different approach to building and designing GPUs than NVIDIA, it's simply building one market segment lower."

We've got a lot of discussion on efficiency between AMD and NVIDIA coming up in this article, although AMD's die is noticeably smaller than NVIDIA's - as you've already seen with the Radeon HD 4850 - there are many areas where RV770 can go toe-to-toe with NVIDIA's mammoth GT200.

Index Building a RV770
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  • DerekWilson - Wednesday, June 25, 2008 - link

    it looks like the witcher hits an artificial 72fps barrier ... not sure why as we are running 60hz displays, but that's our best guess. vsync is disabled, so it is likely a software issue.
  • JarredWalton - Wednesday, June 25, 2008 - link

    Again, try faster CPUs to verify whether you are game limited or if there is a different bottleneck. The Witcher has a lot of stuff going on graphically that might limit frame rates to 70-75 FPS without a 4GHz Core 2 Duo/Quad chip.
  • chizow - Wednesday, June 25, 2008 - link

    It looks like there seems to be a lot of this going on in the high-end, with GT200, multi-GPU and even RV770 chips hitting FPS caps. In some titles, are you guys using Vsync? I saw Assassin's Creed was frame capped, is there a way to remove the cap like there is with UE3.0 games? It just seems like a lot of the results are very flat as you move across resolutions, even at higher resolutions like 16x10 and 19x12.

    Another thing I noticed was that multi-GPU seems to avoid some of this frame capping but the single-GPUs all still hit a wall around the same FPS.

    Anyways, 4870 looks to be a great part, wondering if there will be a 1GB variant and if it will have any impact on performance.
  • DerekWilson - Wednesday, June 25, 2008 - link

    the only test i know where the multi-gpu cards get past a frame limit is oblivion.

    we always run with vsync disabled in games.

    we tend not to try forcing it off in the driver as interestingly that decrease performance in situations where it isn't needed.

    we do force off where we can, but assassins creed is limiting the frame rate in absentia of vsync.

    not sure about higher memory variants ... gddr5 is still pretty new, and density might not be high enough to hit that. The 4870 does have 16 memory chips on it for its 256-bit memory bus, so space might be an issue too ...
  • JarredWalton - Wednesday, June 25, 2008 - link

    Um, Derek... http://www.anandtech.com/video/showdoc.aspx?i=3320...">I think you're CPU/platform limited in Assassin's Creed. You'll certainly need something faster than 3.2GHz to get much above 63FPS in my experience. Try overclocking to 4.0GHz and see what happens.
  • weevil - Wednesday, June 25, 2008 - link

    I didnt see the heat or noise benchmarks?
  • gwynethgh - Wednesday, June 25, 2008 - link

    No info from Anandtech on heat or noise. The info on the 4870 is most needed as most reviews indicate the 4850 with the single slot design/cooler runs very hot. Does the two slot design pay off in better cooling, is it quiet?
  • DerekWilson - Wednesday, June 25, 2008 - link

    a quick not really well controlled tests shows the 4850 and 4870 to be on par in terms of heat ... but i can't really go more into it right now.

    the thing is quiet under normal operation but it spins up to a fairly decent level at about 84 degrees. at full speed (which can be heard when the system powers up or under ungodly load and ambient heat conditions) it sounds insanely loud.
  • legoman666 - Wednesday, June 25, 2008 - link

    I don't see the AA comparisons. There is no info on the heat or noise either.
  • DerekWilson - Wednesday, June 25, 2008 - link

    the aa comparison page had a problem with nested quotes in some cases in combination with some google ads on firefox (though it worked in safari ie and opera) ...

    this has been fixed ...

    for heat and noise our commentary is up, but we don't have any quantitative data here ... we just had so much else to pack into the review that we didn't quite get testing done here.

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