Efficiency

Using the efficiency results from the previous page, we plotted a chart showing the efficiency of the DPS-850 at low loads and at loads equal to 20%-110% of the PSU's maximum-rated load.



The DPS-850 managed to take the lead from its direct Platinum competitor, the Corsair AX860i, at low loads. However, the tide turns in favor of the Corsair unit at normal loads, as it should since it has a higher efficiency rating. The DPS-850 still scores a very high efficiency score at normal loads; it is close enough to the Gold and Platinum competition in its high-end category.

Efficiency at Low Loads

In the next tests, we measured the efficiency of the DPS-850 at loads much lower than 20% of its maximum rated load (the lowest load that the 80 Plus Standard measures). The loads we dialed were 40 W, 60 W, 80 W, and 100 W (for PSUs with over 500 W of capacity). This is important for settings where the PC is in idle mode with Power Saving turned on.


Efficiency was fantastic at low loads, and the PSU's fan only spun at minimum speed, which produced nearly no noise.

DPSApp Screenshots

Screenshots of the DPSApp software follow. The order of the screenshots is the same as the order of the tests shown in the above table (low load efficiency test #1 to test #4).

5VSB Efficiency

The ATX spec states that the 5VSB standby supply efficiency should be as high as possible and recommends 50% or higher efficiency with 100 mA of load, 60% or higher with 250 mA of load, and 70% or higher with 1 A or more of load.

We will take four measurements: one at 100, 250, and 1000 mA, each, and one with the full load the 5VSB rail can handle.


The 5VSB rail is among the most efficient ones we have ever tested. This platform's OEM did a terrific job here!

Power Consumption in Idle & Standby

In the table below, you will find the power consumption and the voltage values of all rails (except -12V) when the PSU is in idle mode (powered on but without any load on its rails) and the power consumption when the PSU is in standby mode (without any load at 5VSB).


Phantom power in standby is low, easily meeting the requirements of the ErP Lot 6 2013 directive.

Fan RPM, Delta Temperature & Output Noise

The cooling fan's speed (RPMs) and the delta difference between input and output temperature are illustrated in the following chart. The following results were obtained at 38°C-45°C ambient.



A chart that shows the cooling fan's speed (RPMs) and the output noise follows. We measure the fan's noise from 1 meter away, inside a small custom-made anechoic chamber whose internals are completely covered in specialized soundproofing material (Be Quiet! Noise Absorber Kit). The background noise inside the anechoic chamber was below 30 dBA during testing. and the results were obtained with the PSU operating at 38°C-45°C ambient.



The following graph illustrates the fan's output noise throughout the entire operating range of the PSU. The same conditions of the above graph apply to our measurements, but the ambient was between 28°C and 30°C.



At normal ambient temperatures, the DPS-850 features a really silent operation that will please even the most demanding noise hater.