I have 2 bfg 7600gts in SLI. Here is my problem. Everytime I overclock, i get very high and stable clocks with ATI Tool but then when i try to run 3dmark06, my comp hangs and reboots. Is this normal? 3d mark will only run at stock settings. Keep in mind these are volt modded cards but they did this before modding too. Should i just try to return them or sell them?