The Dark Knight: Intel's Core i7

X58 Multi-GPU Scaling

While we had some hope earlier in the year of unifying our SLI and CrossFire testbed under Skulltrail, we had to scrap that project due to numerous difficulties in testing. Today, we have another ray of hope. Having a single platform that will allow us to run both SLI and CrossFire would give us better ability to compare multiGPU scaling as there would be fewer variables to consider.

So we did a few tests today to see how the new X58 platform handles multiGPU scaling. We have compared CrossFire on X48 and SLI on 790i to multiGPU scaling on X58 in Oblivion and Quake Wars to get a taste of what we should expect. And the results are a bit of a mixed bag.

With Enemy Territory: Quake Wars, we see very consistent performance. Our single card numbers were very close to the numbers we saw on other platforms, and the general degree of scaling was maintained. Both NVIDIA and AMD hardware scaled slightly better on X58 here than on the hardware we had been using. This is a good sign that the potential for accurate comparison and good quality multiGPU testing might be possible on X58 going forward.

But there there's the Oblivion test.

Under Oblivion, NVIDIA hardware scaled less on X58, and our AMD tests were ... let's say inconclusive.

We have often had trouble with AMD drivers, especially when looking at CrossFire performance. The method that AMD uses to maintain and test their drivers necessitates eliminating some games from testing for extended periods of time. This can sometimes result in games that used to work well with AMD hardware or scale well with CrossFire to stop performing up to par or to stop scaling as well as they should.

The consistent fix, unfortunately, has been for review sites to randomly stumble upon these problems. We usually see resolutions very quickly to issues like this, but that doesn't change the fact that it shouldn't happen in the first place.

In any event, the past couple weeks have been more frustrating than usual when testing AMD hardware. We've switched drivers 4 different times in testing, and we still have issues. Yes, 3 of these four drivers have been hotfix beta drivers, but for people with Far Cry 2 the hotfix is all they've got, which is still broken even after three tries.

We certainly know that NVIDIA doesn't have it all right when it comes to drivers. But we really feel like AMD's monthly driver release schedule wastes resources on unnecessary work that could be better used to benefit their customers. If we are going to have hotfix drivers come out anyway, we might as well make sure that every full release incorporates all the fixes in every hot fix and doesn't break anything the last driver fixed.

The point of all this is, our money is on a lack of scaling under Oblivion due to some aspect of this beta driver we are using rather than scaling on X58.

As for the NVIDIA results, we're a little more worried about those. It could be that we are also seeing a driver issue here, but it just could be that Oblivion does something that doesn't scale well with SLI on X58. We were really surprised to see this as we expected comparable scaling. As the driers mature, we'll definitely test the issue of multiGPU scaling on X58 further.