ATI has released a new set of Catalyst drivers (3.8) that although don't seem to improve performance much, ATI has worked out a few bugs and optimizations for applications that use the Z-buffer.
ATI is also introducing a new feature called OverDrive. As stated on this article at Anandtech: "The basic principle of OverDrive is that the GPU can run at higher clock speeds if it is running cool enough, so as long as the chip is cool enough it will safely overclock."