Alongside the usual performance tweaks in varying game titles etc. there is said to be several Vista related improvements with these as well, particularly with regard to OpenGL.
Catalyst™ 7.3 introduces OpenGL CrossFire™ support for the entire ATI Radeon™ X1000 product series under Microsoft Vista. Users will see significant performance gains in a number of applications when running in CrossFire™ mode under Windows Vista.
Catalyst™ 7.3 includes CrossFire™ enhancements for Windows Vista that enable the Alternate Frame Rendering (AFR) CrossFire™ rendering mode by default, enabling performance benefits for all AFR compatible applications immediately (including newly released applications that have not been officially profiled for CrossFire™). Future Catalyst™ releases will add further CrossFire™ performance gains once new applications have been profiled specifically for CrossFire™.