Be Quiet! Dark Power Pro 650w 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 (in watts) that was applied to the Dark Power PRO 650w during testing.
A common practice among some manufacturers is to “over-volt” the rails on their PSU’s. This often leads end-users to believe that they have purchased a high quality PSU just because it can maintain voltages above the rated outputs (3.33v, 5.00v & 12.00v), when in reality the manufacturer has simply set the idle voltages as high as possible just to compensate for fluctuation under load.
From the graphs above, it is clear to see that Be Quiet! is not one of this companies. With idle voltages almost exactly on their ideal levels across and very little fluctuation under full load, the Dark Power PRO performs just how a high quality PSU should.
Efficiency Results
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 upward slant of the line graph above, the efficiency of the Dark Power PRO improves as the load increases. Be Quiet! state that the unit is able to deliver up to 88% efficiency, and the results obtained from our own tests certainly suggest that is able to come extremely close to that figure.
Temperature vs Fan Speed
As with all components in the modern computer system, the performance of a PSU can be directly affected by heat. Excess heat inside the PSU can easily have a negative effect of the maximum power output of the unit and lead to voltage instability. For this reason, Overclock3D includes temperature recordings taken from the PSU’s exhaust using a thermal probe to highlight any potential issues that the PSU might have obtaining its rated output.
Under normal circumstances we’d also use a sound meter to record the dBA noise level output by the fan. However, the Dark Power PRO was so damn quiet it was simply impossible to take a reading from the PSU without the low-level ambient noise affecting the results. Even with the voltage of the cooling fan inside the unit ramping up from 4.66v to 10.97v at full load, the unit was barely audible. I can say without a shadow of doubt in my mind that this is one of, if not THE most silent PSU ever tested here at Overclock3D.
