Windows Vista Performance Guide

A Few Notes on Graphics

While performance under CPU-limited situations is solely in Microsoft's hands, the same is not true about graphics performance. Due to the need to undertake massive driver rewrites for the new Windows Display Driver Model (WDDM) API, all of the GPU makers have been spending the last couple of years hammering their drivers into shape for Vista with varying results. What has changed and where we're at depends a great deal on what company we're talking about.

AMD

AMD has chosen to use the Vista ramp-up to work on their OpenGL drivers and the widely-loathed Catalyst Control Center. Their OpenGL driver in Vista is what AMD is calling a re-architected driver, something we've been hearing rumors about for quite some time now. Although eventually we expect AMD's efforts with their OpenGL driver to pay off, this is something that will happen in the future, not today. Their new driver is stable and compatible but it's still rough around the edges; AMD has made it clear not to expect it to match their XP performance for a while. On the DirectX front, performance is closer, but AMD has actually told us that Microsoft expects gaming performance on Vista to be 5% to 10% short of XP performance (due in part to the changes brought about by the new WDDM).

As for the Catalyst Control Center, complaints about its long load times and high resource usage did not fall on deaf ears, resulting in AMD rebuilding it for Vista. The result is something that's still not going to rival the old ATI Control Panel or 3^rd-party tools like AMD Tray Tools, but it is a greatly improved package that helps rectify CCC's biggest flaws. AMD has claimed a load improvement on the order of 400%, and while we can't immediately confirm that number we can confirm that it is much faster to load. Startup times are now reasonable for the GUI at about 4 seconds on our X6800 system, and the system tray version is fast enough that most users will be satisfied with it. This is being back-ported to XP as of the Catalyst 7.2 drivers in February, at which point we'll be able to better gauge the difference.

The CCC has also picked up a couple new features in the redesign, the first of which is a new Installer solely for Vista. The main attraction here will be that the installer is no longer a collection of multiple installers for GPU drivers, VIVO drivers, and the CCC, but instead it's one installer that can handle multiple items directly, making the whole installation process faster and a requiring a little less attention from the user. The 3D preview has also been updated; the car scene has been replaced with a side-by-side courtyard scene that in our opinion does a better job at showing the difference between two modes. The car preview was also programmed using OpenGL, whereas the courtyard uses DirectX.

It's worth noting that with this first version of the Catalyst suite for Vista, a couple of things are still outright broken/not-included. Chief among these is complete CrossFire support, as right now it's missing under OpenGL entirely. The universal AFR mode is also absent right now, meaning that it's back to profile-based CrossFire for the moment. Both of these features will be put back in at a later date. Also missing exclusively for Vista x64 is HDCP path support - HDCP is a big issue for Vista since it fully supports the standard, and while HDCP path support is in the 7.1 Catalysts for Vista x86, it will not be in the x64 version until the 7.3 drivers in March. Movies should still be watchable with a 3^rd-party application like PowerDVD or Intervideo, but the ability to play protected content directly will not be there.

NVIDIA

For NVIDIA, they have not used the Vista migration to launch such sweeping changes. Going into Vista they had two driver sets: one for the G80-based 8800 series and another for everything else. Now with the new Vista WDDM, they have four driver sets to maintain. As a result what features are and aren't working depends on the video card used, as some additional features work for the 8800 series that aren't yet working for previous cards. This isn't entirely surprising given that the 8800 series needs to support Shader Model 4, which means extra attention has gone into it anyhow. During the lifetime of the new 100 series driver, NVIDIA plans on merging its code back into a unified driver architecture, leaving out support only for end of life products like the FX series and earlier models. This will certainly be nice, but for now they are still stuck with juggling multiple packages.

For all cards, due to the now-exclusive use of the Vista control panel NVIDIA introduced last year, a few features are missing. Overclocking is not supported, and neither is GPU temperature monitoring or custom monitor timings. TurboCache memory usage is also capped at 255MB for systems with 1GB of RAM and 271 for 2GB or more, so cards capable of using 512MB will not be able to access it all. SLI support either exists or does not exist, again depending on the card. The 8800 series cards now have SLI support, while everything else does not. This will be taken care of in the future, but in the mean time it's especially problematic for GX2 cards which require SLI in order to reach their full potential.

For both parties, it's clear that they still have some ground to cover. As we'll see in the benchmarks, performance is generally good, but at least initially it's going to need to be judged on a per-game basis. Generally speaking, the more popular the game, the more likely it will run well on Vista.