Hd 5970 and power supply

Also with them antecs they usually have many low amp 12v rails, it should say some where on your power supply the amps of each of the +12v rails, you might have +12v1 28 amps +12v2 28 amps +12v3 20 amps +12v4 20 amps or something of that configuration, so when you plug things in you should try to figure out what plugs are on what rails and reserve 2 of the highest amperage rails for just your video card and plug all your other things into the other remaining rails.

If you do decided to buy another psu try to get one with a single +12v rail with high amperage. I have read reviews and they say they are the best to get.

I have a asus ati 5970 and i have it overclocked to 950 MHz core 1.2volts and 1150 MHz memory at 1.15volts and my psu is managing to handle this, I have a ultra x3 1000w and it has a single +12v rail at 70 amps. When I up volts on the core to 1.3 volts and overlcock to 1000MHz my psu starts to make a high pitch but low audiable noise and games arent stable and will eventually lock up computer so I think im at the limit of my psu. I monitor temps and they stay below the limits, cause im liquid cooling. But from what I read is the 6 pin + 8 pin + pci is only designed to handle up to 300watts of power, but I read you can get more then that if you have a psu with higher amps on a single rail. The stock speeds of the card reach max load of 294watts so ati already pretty much to the card to its limits. So im guessing im somewhere between 350w to 400w on my card.