Don`t know why it should be doing that, done the usual i take it, latest drivers....Omega drivers seem to be best for ati if not cat 3.10, directx 9b...all other drivers upto date...if that fails, i know i had this problem but not so bad, just slow...is that you have to installed everything...i mean a fresh install of windows and then go from there...
When i went from a nvidia to ati, the old nvidia drivers kept crashing my system somehow...did a fresh install and haven`t had any problems since
Hope this helps
Later
Ian
Coolermaster HAF XM Case | Asus Sabertooth Z77 Board | Intel i7
3770K@4.2ghz | Thermalright Silver Arrow | 8gb Corsair 1600mhz DDR3 | nVidia GTX 480 | 2x60gb Corsair Force GT SSD in RAID0 | 2xSeagate 1TB HD | Logitech G25 Wheel