Corsair HX 850W Overkill?

[atomictom]

If your at all worried about efficiency and your not gonna go for SLI then a lower wattage PSU(like the suggested 500w) would be better since i believe that the nearer it is to your actual max consumption the more efficient it is. If not good luck to you and your conquest against your power bill and the environment

[Pob255]

The efficiency curve depends on the psu design some have peak efficiency around 40% load others peak around 70% and anywhere in between.
It's generally around 50% because this is the highest point in the 80plus certificate tests
Also as 80plus test start at 20% load the efficiency on most psu's tends to drop off below 20% load

For that system you're looking at around 85w idle

[JamieH]

Probably enough for quad-SLI, let alone a few future upgrades!

Yeah true haha! I didn't really know what to get at the time when my old 530W Hiper gave up the ghost (or so I thought). So just bought the biggest at the time.

The 530W Hiper was (and still is) more than enough.