Some of the performance improvements:
Open GL performance improves for all ATI Radeon X1000 series products. Gains of up to 25% in Doom 3, 48% in Quake 4 and 21% in Prey can be seen on a variety of ATI Radeon X1000 cards. These performance gains are noticed under the Windows Vista operating system.
Full release details of the Catalyst 7.2 over here.