It looks like we're in store for a serious speed up when it comes to Windows 7. While previous talk revolved around GPU acceleration, Microsoft is now implementing something called the WARP system, which will make it so DirectX 10 acceleration can occur on the CPU alone.
Apparently, part of the reason for the WARP is to stave off some of the problems Vista occurred when some systems couldn't run the OS, even though the spec list said they could. WARP stands for Windows Advanced Rasterization Platform. This system will work fine on systems with just an 800MHz processor.
Microsoft has already performed some Crysis benchmark tests on the new system and the results were quite impressive with 7.36fps frame rate with 800 x 600 on a PC running Core i7. This is better than the current Intel integrated graphics have been able to produce. And while this certainly isn't an alternative to a dedicated GPU, it is a decent built-in solution.