Efficiency

Using the efficiency results from the previous page, we plotted a chart that shows the DQ1250's efficiency at low loads and at loads equal to 20% -100% of the PSU's maximum-rated load.



Efficiency at low loads definitely isn't this PSU's strong point, but it easily meets the rest of the Platinum-certified competition head-on with normal loads.

Efficiency at Low Loads

Our next tests measure the DQ1250's efficiency at loads much lower than 20% of its maximum-rated load (the lowest load the 80 Plus Standard measures). The loads we dialed were 40 W, 60 W, 80 W, and 100 W (for PSUs with a capacity over 500 W). This is important for settings where the PC is in idle mode with Power Saving turned on.

Loads below 100 W obviously aren't a 1.25kW PSU's forte, but the DQ1250 still managed to perform admirably in these tests. Efficiency dropped below 70% with 40 W, but performance in our other three tests was considerably better.

5VSB Efficiency

The ATX specification states that 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 DQ1250's 5VSB rail is incredibly efficient. It even managed to crack the 80% mark in the last two test, which is pretty hard for this rail.

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).

No surprises here as the DQ1250 easily meets ErP Lot 6 2013 requirements.

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 39°C-47°C ambient.



A chart that shows the cooling fan's speed (RPMs) and the output noise follows. We measure fan noise at a distance of 1 meter, inside a small custom-made anechoic chamber whose internals are completely covered in specialized soundproofing material (Be Quiet! Noise Absorber Kit). Background noise inside the anechoic chamber was below 20 dBA during testing, and the results were obtained with the PSU operating at 39°C-47°C ambient.



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



Made possible because its Platinum platform hardly suffers energy losses, which results in an incredibly relaxed fan profile, the DQ1250 is among the quietest high-wattage PSUs we have ever tested.