An important tip from one of our users: don't just check total power output, find out what you need in the way of current on each power rail. If you need 20 A on your +12V rails and the supply only has 15A, it doesn't matter how many watts the supply puts out: don't buy it. Make certain that you have ENOUGH rails, too: sometimes, you need more than just two +12V rails for your setup.
Replacing an existing power supply is easier: just get a replacement that meets or exceeds the specifications of the old one. (You can usually find those printed on the side of the supply.)
That said, here's a power supply that is compatible with most ATX format motherboards, puts out 650 watts of power (see specifications for exact distribution). Could this be your next power supply?
ATX12V v2.2 and EPS12V CompatibleCompatible with the ATX12V v2.2 and EPS12V standards, the Thermaltake Toughpower W0128RU provides maximum power stability to drive the latest Intel and AMD processors as well as other components for desktop and entry-level server computer systems.
650W Maximum PowerThe Thermaltake Toughpower W0128RU provides a maximum power of 650W to deliver safe, reliable output for high-end computer systems.
Highly EfficientProviding up to 85% power efficiency, the Thermaltake Toughpower W0128RU power supply saves energy and may even reduce your electric bill!
Efficient CoolingThe Thermaltake Toughpower W0128RU features a silent 140mm fan that delivers highly efficient cooling for the power supply and the whole system while remaining quiet operation.
Intelligent Cable Management SystemThe intelligent modular cable management system allows use of only the cables you need resulting in improved internal airflow and reduced system clutter.
1 x Main connector (20+4 pin) 1 x 12V(4+4pin) 7 x peripheral 6 x SATA 1 x Floppy 2 x PCI-E
Features
Features
Dual Core CPU ready Next generation four +12V rails(12V1, 12V2, 12V3, 12V4) supports high-end graphic card and PC system (combined loading of 52A) Independent Voltage Circuit: offers unflappable current delivery under heavy load and makes voltage output more stable Active Power Factor Correction (PF>0.99) and high efficiency (up to 85%) Extremely good voltage regulation (±3%): provides steady voltage for system Industrial grade components (capacitor, transformer, etc) Mirror effect housing and reliable 14cm ball-bearing fan Protections: Over Current, Over Voltage, and Short-Circuit protection