http://eu.msi.com/power-supply-calculator/Here's a good tool to find out how what PSU you'd need to power all your stuff, i'd suggest doing this then multiply the result (in watts) by 1.2 and round it up, then your on the safe side.
It suggests i need 503 watts for my rig, so :
503 x 1.2 = 603.6 so i suppose a 600 watt PSU would be enough but if i was buying a new one i'd probably got for 650-750watt.
My current PSU is 750watts, so i know i'm good here
