Corsair CX400W Power Supply

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These recordings were made as 24-bit / 88 kHz WAV files with a high resolution, lab quality, digital recording system inside SPCR's own anechoic chamber (11 dBA ambient), then converted to LAME 128kbps encoded MP3s. We've listened long and hard to ensure there is no audible degradation from the original WAV files to these MP3s. They represent a quick snapshot of what we heard during the review.

These recordings are intended to give you an idea of how the product sounds in actual use — one meter is a reasonable typical distance between a computer or computer component and your ear. The recording contains stretches of ambient noise that you can use to judge the relative loudness of the subject. Be aware that very quiet subjects may not be audible — if we couldn't hear it from one meter, chances are we couldn't record it either!

Each recording starts with 6~10 seconds of room ambient, followed by 10 seconds of the product's noise. For the most realistic results, set the volume so that the starting ambient level is just barely audible, then don't change the volume setting again while comparing all the sound files.

Sound Recordings of PSU Comparatives in the Anechoic Chamber


Electrically, the Corsair CX400W performed solidly throughout the testing, including the cross-loading. It produced amazingly low ripple and noise, and maintained excellent voltage regulation throughout. It had no trouble producing full rated power and staying cool on the cool test bench or inside the extremely hot test box. Our sample lived up to all but one of the selling features that we could test (11.4 years MTBF, really?).

Acoustics was the only aspect of its performance that was not remarkable. A couple of years ago, below 25 [email protected] at up to 150W would have been enough to qualify a PSU as a genuinely quiet model. But standards have improved, and the overall noise of the quietest PSUs in the marketplace is now not only lower but lower to a high power load than ever before. In this context, the CX400W feels a little dated. Its controller sped up the fan speed at a much lower power level than we expected.

Keep in mind that this is a bargain-priced power supply, in the lowest price bracket of brand name power supplies, and the CX400W's idle noise is still quite low. Its electrical performance (other than efficiency) up to rated power is competitive with the very best PSUs money can buy. At $50, an 80 Plus-certified, rock solid power supply that is quiet at low power draw is quite a value — and a good candidate for fan modding in a silent PC enthusiast's special project. The CX400W cleanly rounds out the lower-end PSU offerings from Corsair.

Corsair CX400W Balance Sheet


* >80% efficiency in typical use
* Quiet at low to medium loads
* Solid electrical performance
* Inexpensive
* Reliable at high test temperatures


* Steep noise/power curve

Our thanks to Corsair for the review sample.

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SPCR Articles of Related Interest:
Power Supply Fundamentals
Recommended Power Supplies
SPCR PSU Test Rig V.4
Sparkle Power's 250W ATX12V 80 Plus SPI250EP
Enermax Eco80+ 500W PSU
Corsair VX450W: Quiet Value PSU
Nexus Value 430 PSU: Affordable Silence

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