This is not a guide

The most important and obviously overlooked or "mistreated" aspect of computing is usually the PSU. The Power Supply Unit basically proves the way your system will work and supplies all the power to each component for it to work effectively as a complete system. Generic power supplies are the worst bang-for-buck as well as investment, with the majority of problems on a system arising from power surges, overheating, and fried motherboards, components or PSU's. Your PSU will have 12V rails, -12V rails, 5V rails, 3.3V rails. The most important of these is the 12V rails, which power most components including CPU and GPU.

Most importantly you should be looking for the Wattage and Amperage required on the 12V rails as a total and under typical and heavy loads, % efficiency (i.e. DC-AC conversion) not at idle, but under typical and heavy loads, Active PFC, low ripple and adequate->low noise, number of 12V rails, adequate cooling and large well placed fans, the continuous output not "peak" (which is mostly advertised), the manufacturer (very important - would you expect a no frills video card to perform as good as an NVIDIA/ATI?), and something that has been tested and reviewed as stable, verified as a good to buy. These are the very basic requirements where more can also be looked for, such as the heatsink and capacitor qualities, inside the PSU once opened.

Nowadays Graphics Processing Units are requiring the highest power and with Quad Core CPU's, faster 10K RPM HDD's, SCSI and RAID enabled, faster DDR2 RAM and DX10, GDDR4 and DDR3 on the way out; the PSU is now inevitably much more in focus and an extreme requirement. You must have a good PSU to run a computer, matching the requirements fully. Requirements that are met means to add a safety margin on top of your maximum power requirement ever needed by your system. The power output and voltages drop as the strain (time/temperature/load) PSU is used for increases. 25W drop after a year usage is not unknown in good PSU's and is a safe measurement to keep in mind when buying.

Here's a basic PSU power requirements Calculator: Power Calc

Remember to add 30% to the end value it gives before searching for a PSU. You can never have too much, but you can easily have too little or too less.

Good first reads and guides I would recommend are out there everywhere.

"Most" PSU's along the lines of Seasonic, Antec, Sparkle, FSP Forton, PC Power & Cooling, Enermax, Cooler Max iGreen, OCZ, Tagan, BFG, Silverstone are pretty good starting points, if not excellent.

ANY Seasonic and PC Power & Cooling PSU is supreme quality and arguably the best one can purchase out there.

We have already seen the release of a 2000W PSU from Ultra this year, in preparation for the coming exciting year. And I personally have a 5 12V rail, 1000W Enermax Galaxy on my fastest and most hungry system, to compensate.


I believe this should be a sticky not as a guide (thats not what was intentioned here), but because of the link to the calc - please