Greetings I have an sapphire x1800gto and i've discovered that when i overclock the gpu i can go to 612 mhz stable at 1.2 v (74º C on the gpu, 4 hours of atitool with no artifacts). When i overclock the memory i can go to almost 700 mhz @ 2.1 v (495 mhz stock) (i didn't try further). If i put the two of them together (gpu + mem), both atitool and ATT go crazy finding artifacts after a few seconds. It seems my PSU can't handle much... Right now i've to work at 560/612 core/mem @ stock voltages and it seems to be stable (2 hours of atitool scan) .. However ATT still artifacts after 1000 - 1100 seconds. Could it really be the PSU? I find it strange...550 w and 34 amp in the +12 rail (+12v1=16 amp ; +12v2=18 amp), should do more than enough... The gpu is cooled by an zalman vf700 cu.. so taking the temperature away it only leaves the PSU..right?