PC power supply specialist CoolerMaster has become the first manufacturer of gaming-friendly PSUs to win a Silver rating from US energy efficiency monitor 80 Plus.

CoolerMaster's RS-900-AAAA-A3 - part of its Ultimate line - is rated at 900W. That's the sort of power output you need to run a top-of-the-line processor and a couple of graphics cards.

The company's not the first PSU maker to achieve 80 Plus Silver certification - both NXP Semiconductor and Dell have, between them, three PSUs on the list. But these are rated at just 255-270W.

CoolerMaster's Ultimate: very efficient

The 80 Plus Silver rating requires PSUs to show an energy efficiency of at least 85 per cent went measured at 20 per cent, 50 per cent and 100 per cent loading.

The organisation's Gold rating - 87 per cent efficiency at 20 per cent loading, 90 per cent efficiency at 50 per cent loading and 86 per cent efficiency at 100 per cent loading - has yet to be attained by a PC PSU.

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The RS-900-AAAA-A3 scored an average efficiency of 86.52 per cent and was rated as 88.14 per cent efficient at 50 per cent loading. That half-way loading is considered a typical usage by 80 Plus' tester, the Electric Power Research Institute, based in Knoxville, Tennessee.

You can see the CoolerMaster PSU's test sheet here (PDF).

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