Which computer power supply? How many watts?

ATX power supplies have an efficiency curve that peaks somewhere about the 80% capacity mark, ie; your system draws 160W - you want a 200W power supply to get maximum efficiency (less power wasted as heat). Of course different PSUs have different efficiency curves, and systems will draw dynamically changing amounts of power. The fact remains that a 300W power supply from a good manufacturer will run most systems today with no problems, including quad cores and 8800 cards. People claiming that you need 500/700/1000W PSUs do not know a damn thing about computers or electronics. The power supply companies tell people they need a bigger PSU as the profits are bigger, and moronic consumers think higher numbers = bigger penis. It's mere bragging factor. A 350 watt PSU will be more than enough for your system, I saw a Seasonic one on sale for a tenner a few weeks ago at www.ebuyer.com, but to be honest, if your system is more than a year old and not overclocked you could just buy the ...  more