i came to this forum through a search because i undervolted my trifire Ati 6950s to lower temps, as i could afford to lose 10-15 fps in my games.
It was 40 degrees C outside (hot day
) and my vid cards were reaching 80C which isnt bad but its just noisy with 6 vidcard fans all going hard as they each have 2 fans each.
with a mild undervolting and lowing the core clock by 100 and mem clock by 300, i reduced the temps from 80C to 60C and was pretty happy with the results as i only lost 5-10 frames. no instability in my games.
anyhow after i powered up my pc the next morning my mouse cursor would freeze in win7 and then the display would freeze and reboot every 5 seconds or so. i quickly went into afterburner and reset the voltage and clocks to default and restarted my comp.
after it rebooted i was still seeing the same problem so i booted into a winXP install and sadly same freezing and display going blank and resetting.
after pulling apart my $800 trifire setup and trying 2 cards, same deal, swapped out the order of the cards and same deal
pulled em all out and put 1 back in and problem gone, computer works fine. now i will have to see if its 1 faulty vid card that didnt like underclocking or undervolting.