...Windows 7 is the maintenance release of Windows Vista, suggesting a much better experience with most things, including gaming. DirectX 11 represents a major jump, allowing for the graphics processor to do an increasing amount of work like game physics, artificial intelligence, and utilities (like transcoding).
The end result: You'll get a much better gaming experience, much more than the normal improvement you typically just get with a new card. For instance, with multi-threading under DirectX10, one thread would be prioritized and the rest would get whatever performance was left. With DirectX11, performance is balanced between the threads for less bottlenecking. There is also a new instruction set, better HD compression and decompression to preserve bandwidth, and a more aggressive use of tessellation, which allows you to seamlessly zoom...DX11 games promise to be richer, more engaging, and more realistic than their DX10 predecessors, and against their console equivalents, much more current.
