How many watts is enough to power my build?
My build is: http://pcpartpicker.com/p/1jon9
A 500w PSU is enough, but make sure you grab a quality piece from a good manufacturer. I recommend Antec, Corsair, Seasonic or XFX. Here's a great PSU at a good price:
Or if you're on a budget:
This is what I do.
First Google a review of the GPU you plan on buying, ie GTX 650ti;
Then Look at the Max power (Make sure it says SYSTEM
ie GTX 650ti runing metro 2033 = approx 250 Watts
Then add 100 Watts to that value = Min PSU should be 430->450 Watts.
500->600 Extra cussion
NOTE if You plan on runing two GPUs in SLI/Xfire at a later date Then you should google that and add 150 Watts. Except for sli/xfire using the high end gpus a 650 Watt PSU is normally a fine choice.
Next and JUST as important is the Brand/model.
DO NOT buy anything less than a tier 3 PSU, Personlly I limit my choices to tier 2 (tier 1 are great, but generally at a premium cost.)
Tier List: http://www.eggxpert.com/forums/thread/323050.aspx
For a system using a single GeForce GTX 650 Ti BOOST graphics card NVIDIA specifies a minimum of a 450 Watt or greater system power supply that has a maximum combined +12 Volt continuous current rating of 24 Amps or greater and that has at least one 6-pin PCI Express supplementary power connector.
Total Power Supply Wattage is NOT the crucial factor in power supply selection!!! Total Combined Continuous Power/Current Available on the +12V Rail(s) rated at 45°C - 50°C ambient temperature, is the critical factor.
Overclocking of the CPU and/or GPU(s) may require an additional increase to the maximum combined +12 Volt continuous current ratings, recommended above, to meet the increase in power required for the overclock. The additional amount required will depend on the magnitude of the overclock being attempted.