For a system using a single Radeon HD 6850 graphics card AMD specifies a minimum of a 500 Watt or greater power supply. The power supply should also have a combined +12 Volt continuous current rating of 27 Amps or greater and have at least one 6-pin PCI Express supplementary power connector.

Total Power Supply Wattage is NOT the crucial factor in power supply selection!!! Total Continuous Amperage Available on the +12V Rail(s) is the most important factor.

The Corsair Builder Series CX430 V2 (CMPSU-430CXV2), with its combined +12 Volt continuous current rating of 28 Amps and with one (6+2)-pin PCI Express supplementary power connectors, is sufficient to power your system configuration with a single Radeon HD 6850.

Stay away from the Cooler Master eXtreme Power Plus Series because they're all crap. There's a reason why they're cheap and have a shorter than industry average warranty period.
 
Hello jaehwanie;

Guess what? That CM 500 PSU is not a 500W PSU.
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That note below 'combined power shall not exceed' is telling you what it's real rating is.

But it has 30Amps +12V power and the Corsair 430CX has 28Amps +12V power.
CM = 2yr warranty Corsair = 3yr warranty.

Overall, the 430CX has better efficiency and a better reputation.
 

e56imfg

Distinguished

+1

A List of Recommended PSUs
Rosewill Green Series RG430-S12 430W provides more amps and overall power than the CX430 and doesn't have the whine noise that comes with the CX430.
SeaSonic S12II 520 Bronze 520W
CORSAIR Enthusiast Series TX650 V2 650W my pick for future upgrades and maximum efficiency