I have a XFX 8600GTS (Extream not XXX) and my powersupply is 305 watts and dual 12v 18A rails, same as the guy with the E520. Mine is also freezing, It mostly happens Halo and NFS: carbon. It only happens after around 15 minuetes of gameplay. I do NOT think its power, rather i think it is heat realated. First, the fan does not really turn on during heavy gameplay it alwyas stays at a light amount, and second I messured temps and after 10 minutes of 3dmark06 the temps were at ~75c. I have a fealing the fan (if not working correctly) can be fixed in drivers. Also, i tried underclocking (oohh, also, it has never been overclocked past factory which is 720, 2180), and when i try to underclock it says the GPU test has failed. Can someone, hopefuly the very helpful guy from XFX help me.
some extra info:
I have a pentium D 940, 1 CD/DVD drive, one SATA 160 7200RPM HDD, 1 120mm fan, 2 gigs of 533mrz RAM, Vista ultimate, 3dmark06 score of ~5200, and a dell 945G mobo
Also, I used to use a 7600GT and it worked fine
Thanks,
Ares