the Cooler Master PSU is comboed with a HAF 932 Advanced Case ( which I am planning on buying) and will be $41 less than if I buy the SeaSonic
I want to get the SeaSonic because it is such a reputable brand on the internet. but I'm not sure whether 850w will power my rig.
I currently have no budget restrictions so I can afford either one of the PSUs
here's my setup:
Mobo: ASUS P8Z68-V PRO
CPU: i5-2500K ( Planning on overclocking, but no more than 5.0GHz
GPU: HD6950 Crossfire (2 of them)
RAM: G.Skill Ripjaw-X 8GB DDR1333 CAS 7
HDD: Samsung Spinpoint F3 1TB 7200RPM
The Seasonic is definitely an excellent unit and I agree with everything ko888 said. It does pain me how expensive it is, though. Either of these will power your rig just fine for a fair bit less, and both are highly reputed/rated:
The Seasonic X 850 is one of the best psu's that you can really buy. Highly stable, highly efficient, and can actually put out its rated and unrated output nearly always above 80% efficiency.
As ko stated, the CMPSGS psu has higher ripples and is lower quality than the seasonic. When choosing a psu from a company that builds nearly everyone elses top psu's and a company which is a hit or miss depending on their model... I know which one i prefer.