I was having a problem recently that caused games to crash when using my 9600 Pro. Anyway the problem seemed to be solved when AGP write was disabled in the Smartgard utility (not Smartgart). This isn't the same as Fast Writes as the is an option to disable this also.

What do AGP read and write do?

Note: to run SmartGard you need to browse to the ATI contol panel folder (usually in program files) and execute the SmartGard program. it gives you options that aren't available through the dsiplay properties.