This is a pretty good driver as far as performance increases go for Vista users. Crysis sees a very nice bump in performance and so does UT3. CINEBENCH also sees gains but the OpenGL increase isn't carried over to our OpenGL based game Enemy Territory: Quake Wars.
The Windows XP driver on the other hand seems to be horrendous for X2 users with some severe power drops. We tried multiple X2 cards and tried the other Catalyst drivers and the dropped score in a few key benchmarks were consistent on the 8.3s.
There is also the added bonus of Crossfire X support now which we have had a brief look at with a pair of HD 3870 X2 cards recently.
On a whole, the Vista driver is very good but the XP variant is a bit of a letdown. It will be interesting to see what happens with the Catalyst 8.4s due next month.
Until then, it might be time to fire up Crysis and bump up a setting or two.