James Yu and Sarju Shah - Posted on Tuesday, January 30, 2007.

The general public may struggle with the decision over whether to move from Windows XP to Windows Vista, but there isn't much to agonize over for PC game fans--if you want to play games with advanced DirectX 10 graphics, you're going to have to upgrade to Vista. Windows XP owners will be left behind in the graphically inferior world of DirectX 9 once Vista arrives. The real debate for PC game fans is when to upgrade to Vista.

For PC gamers, Windows Vista is pretty much a next-generation gaming platform launch happening in slow motion. The operating system has been available since last year as a closed, then public, beta, and the hardware arrived last November, when Nvidia shipped the world's first DirectX 10 GPUs, the GeForce 8800 GTX and GeForce 8800 GTS. The cards themselves shipped with excellent Windows XP drivers, but Nvidia held off on releasing Vista drivers until now. The actual OS and hardware package finally came together today for the official launch of Windows Vista.

Vista's marquee DirectX 10 games aren't scheduled to arrive until later this year. Crysis, Crytek's visually stunning jungle shooter, has a summer launch window, and Age of Conan: Hyborian Adventures, an action adventure MMO, should be coming out this fall along with Hellgate: London. Supreme Commander has already gone gold, but the DX10 graphics game update won't arrive until March. Flight Simulator X and Company of Heroes will also get DX10 updates in the coming months.

We still don't know how the first DX10 games are going to look. Giving the graphics engine access to virtual memory will open the door for superhigh-resolution textures, and the geometry shader will make it easier for games to generate complexity; but many of the changes in DX10 will yield performance improvements rather than new graphical effects. The initial DX10 games will look better than DX9 games only if developers actually invest the newly freed power into additional onscreen clutter or more-sophisticated shader effects.

Mouse over the Age of Conan DirectX 9 image to see the DirectX 10 comparison shot.

All the DX10 game delays won't mean that early Vista adopters will be left playing Purble Place and Mahjong Titans this spring. They'll still be able to play World of Warcraft: The Burning Crusade and Command & Conquer 3 just like everyone else, since Vista is backward compatible with DirectX 9 games originally made for Windows XP. The hardware manufacturers have been busy making new drivers to make sure all their products work with Vista.

We wanted to see how well games performed in Windows Vista compared to Windows XP. We tested four video cards, ranging from the high-end GeForce 8800 GTX down to the mainstream Radeon X1650 Pro, to see how Nvidia's and ATI's Vista drivers compared to their XP counterparts. We also compared the operating systems using different amounts of system memory because we wanted to see if Vista's increased memory usage hindered game performance. Note that we're only examining DX9 game performance in this feature, and we're in the process of testing OpenGL games for a future update. Visit CNET's complete guide to Windows Vista or our Windows Vista Hands-On preview for an overview of the new operating system.