Microsoft has said that it's enhancing game performance and the games interface in Windows Vista not only because so many people play games on PCs, but also because it wants to change the perception that the PC is a poor gaming platform. Many people believe that if you're serious about gaming, you need to use a dedicated game platform such as an Xbox or a PlayStation. This has seemed even more true with the release of the Xbox 360 and the forthcoming release (as I write this) of PlayStation 3, which offer spectacular graphics and game features.

Can Vista really compete with these dedicated game consoles? I think it can because Vista has a gaming ace up its sleeve: the Xbox 360 and the PlayStation 3 both use the DirectX 9 hardware to render video and audio. However, Windows Vista supports DirectX 10, the latest and greatest version of the APIs, which has been completely rewritten to take full advantage of the powerful graphics hardware that's now available for PCs.

The specifics of what's in the DirectX 10 package were not known as I wrote this, but Microsoft had let a few tidbits out of the bag:

• DirectX 10 removes many legacy functions and interfaces that were kept for backward compatibility but degraded the overall performance of the APIs. As a result (at least as of this writing), DirectX 10 is exclusive to Windows Vista and won't be supported in Windows XP.

• At the hardware level, games programmed for the DirectX 9 and earlier APIs will not work with DirectX 10. However, DirectX 10 will support these legacy programs via software emulation.

• DirectX 10 requires a graphics card that has a specific set of features for maximum performance, so game developers can assume that those features will be present and don't have to weigh down their code with workarounds and other card-specific code.

• DirectX 10 supports impressive new "shader" functions for both pixels and primitives such as dots, lines, and triangles.

• DirectX 10 supports hardware caching of render states, in which thousands of objects can be held in the cache for easy access. This improves performance not only by making more code quickly accessible, but also by minimizing the number of times the game code has to switch from one render state to another.

These and many other changes should produce a significant improvement in game performance. In particular, PC games developed with DirectX 10 should render scenes with amazing levels of detail, shading, reflections, and other elements that will give these games more of a "real-world" feel