Go to Creative and download the fast trak drivers - gives you a lot of options to fiddle with. You will need detonator drivers already installed though, as they are not stand alone drivers.
With these try to under clock your card to see if the core or the memory is duff.( Lower the mem clock and then try the core clock )
P3600e@800 with Alpha PEP66
Iiyama VisionMaster Pro450
Corsair PC2700 cas2