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Bitfenix Whisper Series 550W PSU Review

Bitfenix recently released its Whisper PSU family, which, as it name implies, promises quiet operation. This review focuses on the 550W model, offering 80 PLUS Gold efficiency and fully modular cabling.

Cross-Load Tests And Infrared Images

Our cross-load tests are described in detail here.

To generate the following charts, we set our loaders to auto mode through our custom-made software before trying more than 25,000 possible load combinations with the +12V, 5V and 3.3V rails. The load regulation deviations in each of the charts below were calculated by taking the nominal values of the rails (12V, 5V and 3.3V) as point zero.

Load Regulation Charts

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Efficiency Chart

This is one of the most efficient 550W Gold-rated PSUs we have ever tested. Its best spot is between 175W and 270W, where it delivers over 92% efficiency when the minor rails stay below 25W combined load. The BWG550M is able to exceed 90% efficiency for a much wider range, starting from around 90W to 450W.

Ripple Charts

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Infrared Images

Toward the end of the cross-load tests, we took some photos of the PSU with our modified FLIR E4 camera that delivers 320x240 IR resolution (76,800 pixels).

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Thanks to increased efficiency, temperatures inside the PSU remain low.

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.