be quiet! Dark Power Pro 850w ATX PSU

Load Testing

To provide our readers with the most accurate results, Overclock3D uses a custom built PSU load tester on all reviews. This not only gives much more reliable results than the testing methods employed by other sites, but also allows for all current and future review results to be compared side-by-side. The following table shows the load that was applied to the Dark Power Pro 850w during testing.

With 25% load applied to the Dark Power Pro 850w, both the +3.3v and +5v rails start off slightly high. However as we move to 50% and 75% load levels this evens out with the voltages coming close to their ideal values. Even with 100% load applied the voltages remain well within acceptable levels.

Each of the +12v rails sits almost bang on 12.0v under 25% load. This certainly goes to show that be quiet! don’t believe in over-volting their PSU’s with higher idle voltages to compensate for large amounts of ‘sag’ once a heavy load is applied. However, this does have an adverse effect for the Dark Power Pro when the load is placed at 100%, with +12v3 reporting a quite low voltage of 11.681v.

Efficiency

Efficiency tests are performed by measuring the wattage consumed by the power supply at the mains (Mains Draw) against the power consumed by the OC3D power supply stress tester (PSU Load). These results may not be 100% accurate, but have proven to be extremely close to results obtained from professional equipment.

As we can see from the chart above, the efficiency of the Dark Power Pro 850w seems to peak at around 50% load. While not exactly the 88% efficiency that be quiet! quote in the specifications for the unit, it’s certainly very close and once again places the Dark Power Pro range as one of the most efficient PSU’s we’ve ever tested.

Noise Levels

As you’d expect from a PSU with a name like be quiet!, the Dark Power Pro is extremely silent. At 25% and 50% load levels the 120mm fan spins at a very low RPM an could almost be described as inaudible unless you put your ear up close to it. At 75% load levels the fan does speed up a fair bit to combat the heat build-up inside the PSU, but even at this level the noise emmited is far from unacceptable

Finally, at 100% load the Dark Power Pro does become a fair bit more vocal and can easily be heard across the room. That’s not to say the PSU is loud, because it certainly is not. However, talking about 100% load noise in an 850w PSU is a bit of a dead issue as not many people will be stressing the PSU anywhere near 100% and if they do it will more than likely be with powerful GPU’s or CPU’s – all of which require fairly noisy air cooling solutions.