When you are picking up a high powered PSU, of 1kW or so, you may notice that it is longer than the power supplies you are used to.  Some are large enough to give troubles installing it in certain cases.  OCZ comes through with their ProXStream 1000W PSU, and HotHardware has the review.  It will fit in your case, and the 4 12V rails with 20 amps each will keep your graphics happy.
“‘The unit is amazingly small for a 1000W power supply; as similar units form other companies typically require extended depth designs, which can require larger cases in order to be mounted properly. The OCZ unit, on the other hand, has the depth of a standard ATX power supply, meaning it can be mounted in nearly every standard ATX chassis on the market today.'”

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