Originally posted by: Tig Ol Bitties
If this is your PSU:
http://www.legionhardware.com/pic.php?i...hermaltake_PurePower_460w/Image_04.jpg
You've got 200W dedicated to your +5V and +3.3V rail, leaving you roughly 260W for the remaining rails (the dual +12V rails for the most part). Divide that 260W by 12 and you roughly get your *combined* amperage of an unimpressive 22A. No, you don't have 30A on the +12V rail...you don't sum up the rail's amperages, never works that way and is a common misconception. Basically, you're starving the video card of amperage. I don't consider Thermaltake's lower end PSUs to be very good at all...their Toughpower series are decent though. Any one of these would power your card:
FSP Fortron 450W ~28A for +12V rail
Hiper 480W ~29A
Xclio 500W ...30A
ENERMAX 460W ...32A
The Enermax is easily the best unit here for amperage, but any of these would power a X1950pro. The 30A requirement is rather overstated IMO for quality-branded PSU units. I'm not the least bit surprised that a 480W Thermaltake couldn't handle this card considering its 18A on the +12V rail.
For power supplies with that kind of wattage, the +12V amperages are very unimpressive for a lot of the <500W Thermaltakes. For the X1950pro, I feel a 26A+ is a proper measure for the +12V rail so long as the PSU is a decent brand/model.
Example, the SeaSonic 430W PSU would easily power this card with its 29A through the +12V rails, but the PSU still costs close to $100, so I didn't suggest it....this is one of the few cases where the actual sum of the +12V rails
IS the actual *combined* amperage (+12V1 = 14A, +12V2 = 15A, combined wattage 348W).
Hope this apparently long post helps.