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Old 04-07-12, 06:03 PM   #4
RobertSmalls
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The forum over at Silent PC Review is a great source for information on quiet and low power consumption PCs. I'm not the only SPCR'er who thinks that PSUs have gotten too darned big lately. I'm running a 120W PSU, the PicoPSU. I recently upgraded to a Sapphire Radeon HD 7750, which supposedly requires a 400W PSU. *rolleyes*

What the 7750 actually needs is 3.5A of +12V. Graphics card manufacturers have no way to know how much of your PSU's power is availabe on the +12V rail, nor how much power your CPU will draw, so most of them play it safe and recommend very overpowered PSUs.

That's a problem because a PSU's efficiency curve is not flat. 80+ certification guarantees 80% efficiency above 20% of load, but below that, <70% efficiency is typical. My recommendation would be to try it out with your current PSU (with Kill-A-Watt in place) and see what you get. If the PC locks up while running FurMark, then you'll know for sure.
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