Be Quiet! Dark Power Pro 850W

What's Inside?

The same fluid bearing fan is used from Protechnic Electric (MGT12012LR-O25), although the sub-code is slightly different: from A25 to O25. The fan is 120 x 120 x 25mm in size and we suspect its full 1,800RPM it shifts 61CFM of air at 31dBA. So at full throttle that's quite noisy, but at least it's highly thermally controlled just like the 650W. Two thermal probes from the daughter PCB on the side are screwed to the central heatsinks to check the temperature.

Generally though this fan is extremely quiet and Protechnic is used by several other PSU companies. However, while the blade balance is very good, the fan quality (plastic and spin) is notably lower than that of the Sanyo Denki used in the Seasonic M12D SS-850W.

Inside, the heatsinks are quite large and chunky and it's extremely similar to the 650W build because effectively the same basic PCB underneath is used for everything from 450W all the way up to 1200W. That's quite a degree of variation for the same PCB and footprint, and in this 850W unit the main transformer is significantly smaller than the DC-DC Seasonic for example. The 3.3V/5V are provided by another, smaller transformer just above, though.


The heatsinks are very chunky and long, but the surface area is not as large as other solutions and they lack decent channelling for the air moving towards the exhaust in the back.


CapXon from Taiwan makes the single large 85°C main capacitor - again it's not Hitachi or Rubicon, but the company claims RoHS and ISO certification so it's better than the cheaper Chinese brands. Notably because the modular PCB has to deal with higher power and more PCI-Express connectors - there are now more, tall and slender capacitors to smooth the power drain as well.

Generally the quality inside is very good. It's well built with good quality soldering, but we did find a couple more precarious coils that were prone to more significant wiggle. One thing to note is that there is no potential for this to be a golden sample either - we watched as it was pulled out of a retail pallet from the main warehouse, so this is exactly as you'll get your own.