Hot Box Test Results

This new platform probably delivers the best power quality that we have previously seen from any Channel-Well Technology design. The ripple suppression of the 450W unit is amazing, with the 12V line registering a maximum of 20 mV and the 3.3V/5V barely reading a voltage ripple of 12 mV. 

BitFenix Whisper M 450W - Main Output
Load (Watts) 91.01 W 227.31 W 339.04 W 450.63 W
Load (Percent) 20.23% 50.51% 75.34% 100.14%
  Amperes Volts Amperes Volts Amperes Volts Amperes Volts
3.3 V 1.69 3.36 4.22 3.35 6.33 3.32 8.44 3.32
5 V 1.69 5.06 4.22 5.05 6.33 5.03 8.44 5.02
12 V 6.33 12.13 15.83 12.12 23.75 12.05 31.66 12.01
Line Regulation
(20% to 100% load)
Voltage Ripple (mV)
20% Load 50% Load 75% Load 100% Load CL1
3.3V + 5V
3.3V 1% 8 8 10 12 8 10
5V 0.9% 8 10 10 12 8 12
12V 1% 10 14 16 20 16 12

We can see that the 850W version delivers similar performance under the same loading conditions, with the voltage ripple readings increasing only at loads far beyond the capacity of its smallest sibling. Still, the 32 mV voltage ripple on the 12V line is an outstanding figure under a load of 850 Watts. The voltage regulation is nearly identical for every line of both units, with an average of just 1%.

BitFenix Whisper M 850W - Main Output
Load (Watts) 171.98 W 429.31 W 640.99 W 851.22 W
Load (Percent) 20.23% 50.51% 75.41% 100.14%
  Amperes Volts Amperes Volts Amperes Volts Amperes Volts
3.3 V 2.01 3.4 5.02 3.39 7.53 3.38 10.04 3.37
5 V 2.01 5.1 5.02 5.08 7.53 5.06 10.04 5.05
12 V 12.78 12.12 31.94 12.11 47.92 12.05 63.89 12
Line Regulation
(20% to 100% load)
Voltage Ripple (mV)
20% Load 50% Load 75% Load 100% Load CL1
3.3V + 5V
3.3V 0.9% 8 10 10 12 10 14
5V 1% 8 10 16 16 10 16
12V 1% 10 16 24 34 32 18

The higher ambient temperatures in our hotbox testing had almost no impact on the energy conversion efficiency of the Whisper M 450W PSU at all, with the unit technically maintaining 80Plus Gold efficiency levels even under such conditions. Respectively, the efficiency of the Whisper M 850W PSU dropped by an average of just 0.5%. The drop is a little greater than that of the 450W model, but minimal nonetheless. These figures suggest that the components are of excellent quality and adequately oversized, allowing the Whisper M PSUs to seamlessly operate under the most adverse of system conditions.

Considering the small heatsinks and especially because the 850W version is using the exact same heatsinks as the 450W version, we expected to see higher operating temperatures during our testing. However, it seems that BitFenix went with a simple, yet effective way of fan speed control that completely ignores the load and adjusts the fans only according to their internal temperature.

As a result, the Whisper M units cannot really operate quietly in a very hot environment, but the internal temperatures will always remain at perfectly safe levels.

Cold Test Results Final Words & Conclusion


View All Comments

  • Chaitanya - Wednesday, February 15, 2017 - link

    Those cables certainly look nice, especially the 24pin cable. Reply
  • HomeworldFound - Wednesday, February 15, 2017 - link

    The 24pin cable looks pretty good. The 24pin ATX cable has really gotten annoying for me. Is there no way to further innovate in that area? Reply
  • The_Assimilator - Thursday, February 16, 2017 - link

    Barring another revision of the ATX spec, the best we can hope for is right-angled 24-pin connectors on motherboards a la EVGA. Reply
  • DanNeely - Thursday, February 16, 2017 - link

    As stagnant as the desktop's become about the best we could hope for is to declare about 1/3rd to 1/2 of the pins in the big connector optional (-12v, most of the 3.3/5v, and a few of the corresponding grounds) and have a big sparsely wired connector.

    I'm not sure a right angle 24pin socket is actually a good idea in general. Cable routing is far worse with it in a compact case without wiring space behind the mobo. Even if you have wiring space behind the mobo, it's still a much more cramped space to be trying to make the tight bend you need to get it into position. It also makes having a cable hole mis-aligned with where the mobo connector is a lot more problematic; with a vertical socket you can just feed an extra few inches up to shift to the side, horizontally not so much. Lastly I'd be a bit leary about it just in terms of general strain relief. The great big fat cable can pull on the socket really hard if it's alignment is off and a tall cable loop coming up gives a lot more potential slack to dissipate the force than a tight 180* turn coming through the cable hole.
  • BrokenCrayons - Wednesday, February 15, 2017 - link

    It's easy to overlook a typo on the box to pick up a very reasonably priced PSU with high efficiency and good test results. The absurdly long warranty is a bonus. I think we've got a winner here. Reply
  • jardows2 - Thursday, February 16, 2017 - link

    Maybe it's intentional, and should be read as Perf-Romance - as in you'll fall in love with the "perf" of this product! Reply
  • fire400 - Sunday, February 19, 2017 - link

    lol.. great marketing strategy Reply
  • Drumsticks - Wednesday, February 15, 2017 - link

    How does this compare to the RM550x, which made it onto your best of list last year?

    It looks like a pretty good unit, though, and for a little bit less than the 550x. Hopefully we can see more stock like you said. I can't find it in the US at all.
  • fanofanand - Wednesday, February 15, 2017 - link

    These PSU reviews might not gather as many comments or as much appreciation, but the next time someone is putting together a new build they will appreciate the time and effort spent. BitFenix has been doing some really great things lately and it looks like this PSU will continue that trend. Nice job with this review. Reply
  • wolfemane - Wednesday, February 15, 2017 - link

    I really wish this review had come out just a few days earlier. Wound up getting a RM550x for a bit more. BUMMER! Reply

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