NVIDIA took a lot of flack for their Vista drivers back in Feb, but a lot has changed in the past 7 months. Are NVIDIA's Vista drivers any better? What about AMD's Radeon HD 2900 XT? In this article FiringSquad takes a look at single card and multi-GPU performance in both 32-bit and 64-bit flavors of Vista to see how it compares to Windows XP. Here's a taster:

F.E.A.R. and Oblivion were easily the best case examples for both AMD and NVIDIA. Performance with both of these games was largely similar regardless of the OS tested, whether we were running a single card or with two GPUs. S.T.A.L.K.E.R. didn't scale quite as perfectly as F.E.A.R. and Oblivion under Windows Vista with the Radeon HD 2900 XT and GeForce 8800 GTX, but it was pretty close.

Enemy Territory: Quake Wars ran similarly on all the AMD configs we tested with regardless of OS used, although as we noted last week we witnessed numerous graphical glitches when running this game with CrossFire enabled: basically it runs, but it doesn't always look pretty. NVIDIA's single card performance was excellent in Quake Wars, but under SLI we did notice a performance hit under Vista for the GeForce 8800 GTX and 7900 GT SLI configs. In the case of the GeForce 8800 GTX SLI, performance was off by 8% for 32-bit Vista compared to WinXP at 1600x1200. That margin shrinks to 4% at 1920x1200.

Company of Heroes took a hit of 4% at 1600x1200 with the GeForce 8800 GTX and 5% with SLI but this figure is reduced down to 2-3% at 1920x1200. Honestly though this is such an imperceptible difference that you'll likely never feel it in game.

BioShock is the one title that AMD really needs to work on. As we noted in our BioShock performance articles, DX10 performance is significantly slower than DX9, and the game doesn't scale at the moment with CrossFire. The Radeon HD cards also lack support for AA in BioShock. You have to rename the game's executable in order to force AA, and as we discussed in our BioShock AA article, this disables all of AMD's driver optimizations for BioShock. While we didn't run specific performance comparisons, it seems like NVIDIA's performance in BioShock has improved tremendously with this latest ForceWare driver. We'd guess performance has improved by over 10%. SLI also scales much better than it did previously. We're seeing nearly 2X performance scaling with BioShock and ForceWare 163.69, whereas previously that number was a little under 1.5X. With all that being said though, Windows XP did run up to 8% faster than Vista in our testing. Still, we were very encouraged by these results.