Hello. I have this same problem.
I have a similar card. Before I continue, here are my specs:
Athlon 64 X2 4800+ @ 2.57ghz
Corsair XMS DDR 400 @ 234mhz
HIS ICEQ x1900xt 512mb
Thermaltake Toughpower, 700watt.
3 HD, 2 optical, SB Audigy, 5 case fans.
(Software: Winxppro, cat 7.2 w/...