Be Quiet! Dark Power Pro 650W

Results

Quite simply Be Quiet! has made an excellent PSU - not only are the voltages all green but they are all consistently very high too. The slightest exception is when we 12V weighted only rails one and two with the PSU at 100 percent load - one of the four 12V rails dropped to 11.69V, although this is still well within ATX spec. We ran two sets of 12V weighting to really test the 20 Amp claim and they both came through successfully.

In addition to this, the PFC is very high and efficiency is at 80Plus Silver levels - the PSU is consistently over 87 percent efficiency and averages 87.98 percent efficiency over the entire test span. That’s an incredible result by today’s standards, although it’s worth noting that other manufacturers are also upping their game quite quickly too.

Be Quiet! even includes an additional post-shutdown cool off (ECASO - Enhanced Cooling After System Off), where the fan stays on for up to three minutes to ensure the components are properly cooled. Enermax also does this and brands it CoolGuard, and so do a few other manufacturers but it's not a universal feature.

In terms of its audible nature this thing is damn near silent, and we really do mean that in the truest sense of the word. At 50 percent load you cannot even tell if it's on if it wasn't for the fan spinning. As it rises to 100 percent load, the noise increases a bit but not to anything intrusive. However the temperature of the unit was quite warm even at 50-75 percent and it got quite hot in places at 100 percent load. In a hot case this will be worse, but the fan has plenty of RPM overhead to dive into though.

While sometimes we prefer a good quality single, large 12V rail that supplies everything and always offers the maximum potential, the four 12V rails here are quite applied. 12V1 supplies the motherboard only, 12V2 is for the EPS 12V power cables, 12V3 is for the peripherals and 12V4 is for PCI-Express. The motherboard ATX connector doesn't need an entire 20 Amps of 12V1 to satisfy it to be honest, but the split seems logical enough.