Final Thoughts and Conclusions

The Whisper M 850W power supply is our first look at what BitFenix has to offer in the power supply market. They appear to be targeting main stream PC users with the Whisper M series, shooting for the right balance of high performance, quiet operation, and price.

The BitFenix Whisper M 850W power supply produced very good DC voltage regulation with all three main outputs staying within ±2% of the target values. The power supply also exhibited very good efficiency, easily meeting the criteria for 80 Plus Gold certification, even while operating on 120 VAC and at elevated temperatures. The AC ripple and suppression was also very good.

The Whisper M 850W PSU has a good assortment of fully-modular cables. Even though the power supply comes with four VGA/PCI-E cables and two 4+4 pin CPU cables, there are only five connectors available on the power supply, so you must pick and choose if you need both CPU cables. Another minor complaint is with the large 24-pin ATX connector. The added bulk is due to a trio of small filter capacitors under the hood.

Our main concern is with the cooling fan made by Martech, which we haven't come across in a power supply before. During our initial tests the fan didn't start spinning until we entered the 75% load test and emitted a soft resonant vibration sound. After re-testing the power supply a few days later the fan started spinning at power up. But it still emitted that soft resonant vibration sound. After contacting BitFenix about this issue they immediately sent us a second unit and it performed perfectly. The fan was whisper quiet from start up through mid power.

The BitFenix Whisper M 850W power supply is currently available but it was out of stock at several of the big online retailers when I checked (early February 2018). The MSRP is $119.99 USD, which is a competitive price for an 850 watt power supply.

There is a lot to like about the Whisper M 850W power supply, but we have some reservations about the cooling fan. However, BitFenix feels confident enough in this PSU to back it with a 7-year warranty.

•    Very good voltage regulation (±2% on the three main outputs)
•    Very good efficiency (80Plus Gold certified)
•    Very good AC ripple and noise suppression
•    Japanese made capacitors
•    Fully modular, ribbon style cables
•    Safety protections: OCP, OVP, UVP, OPP, SCP, OTP, and SIP
•    Competitive pricing
•    7-Year warranty

•    Cooling fan reliability concerns
•    Bulky 24-pin ATX connector

BitFenix Whisper M 850W Power Supply

Our thanks to BitFenix for sending us the Whisper M 850W PSU to review.

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