PSU confusion?

Hello guys,
I am looking to buy a decent PSU that will power the 7850 along with the 2500k over clocked to around 4.4 Ghz. I have OCZ's Fatal1ty Series 550W Modular power supply in mind.

Will this support the components listed above? Also, it says that it has a 6-pin and a 6+2 pin PCIe connectors, which gives it a total of 2 connectors for graphics cards. The mini description says that there are 2x 12V rails and that they output a total of 450W, which would mean 225W each. Considering the 7850 only uses one of these 6-pins, and i think benchmarks state that it uses a power consumption of around 230W in games, does that mean it is enough?

It also says that the 2 12V rails are rated at 25A ea. Isn't the conversion of Amps to Watts Ampsx12=Watts? Which would mean they output 300W each as opposed to the 225W? I don't know if i am getting this all muddled up, but can you guys explain it to me?

Sorry for the long read, but hey.
Regards, :)
5 answers Last reply Best Answer
More about confusion
  1. As written on the PSU, the 12V total is 450W and not 600W. A good review of that PSU can be found at
  2. ocz is a good company and yes it will handle that system
  3. Best answer
    For a system using a single Radeon HD 7850 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 26 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 OCZ Fatal1ty Professional Series 550W (OCZ550FTY), with its combined +12 Volt continuous current rating of 37.5 Amps and with one 6-pin and one (6+2)-pin PCI Express supplementary power connectors, is more than sufficient to power your system configuration with a single Radeon HD 7850.
  4. Yes it's sufficient, but I'm sure we can find you something better in the same price range.

    A single large 12v rail is always better than 2 smaller ones.

    Let us know your psu budget and your location and we can find you something more efficient and probably with a better warranty for the same price.
  5. Best answer selected by oddlyinsane.
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