XFX Core 650w hums - flip over PSU?

BattleshipLorenzen

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Dec 23, 2011
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I have an XFX 650w PSU in my system and recently noticed that it, not any of my cheapish fans, is humming. The pitch of the hum makes it audible above any of the fans. I tested some of the PSU with a multimeter (MOBO and 6-pin cords), and the PSU itself gets great review (Seasonic internals). XFX is known for crappy fans, but some people say their XFX 650w PSU's are "silent'.

My specs are below. The fan is facing downward--so it intakes from under the case and blows out the back. The case has feet and is on a wooden table. Think flipping it is worth the effort in case it helps the hum? It's non-modular.

-Case: Zalman z9 Plus
Came with 120mm LED fans in front (1), top (1) and side panel (1). Also has a non-LED 120mm rear fan. I have the side panel on case's fan controller and turned town as far as it goes to avoid that hum; the others are at max all the time (~1200 RPM).
-2500k @ stock
-Corsair A70 cooler /w inline resistors turned down to mobo's lowest setting (@ about 1100 RPM)
-Asrock Extreme3 Gen3 MOBO
-Corsair Force 3 120gb SSD
-Powercolor HD 6850 GPU
Fan set at 10% (360rpm) in speedfan

Thanks for the help!