Efficiency

Using the efficiency results from the previous page, we plotted a chart showing the efficiency of the VP550F at low loads and at loads equal to 20-110% of the PSU's maximum-rated load.



Efficiency at low loads is impressive since it is very close to the reading that the Gold Seasonic G-550 registered, although the VP550F only has the basic 80 Plus certification. Its ranking isn't so good at normal loads, but the PSU still managed to achieve a reading over 86%, which is very good for its class.

Efficiency at Low Loads

In the next tests, we measured the efficiency of the VP550F at loads much lower than 20% of its maximum-rated load (the lowest load that the 80 Plus Standard measures). The loads that we dialed were 40-, 60-, 80-, 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.


As we already mentioned, efficiency at low loads is impressive if the unit's basic 80 Plus certification is taken into account. The only thing we didn't like was the increased noise that the fan made; its speed exceeded 1100 RPMs with even a low 40 W load and reached close to 1300 RPMs in test #4.

5VSB Efficiency

The ATX spec states that the 5VSB standby supply's 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 that the 5VSB rail can handle.


Efficiency at 5VSB easily surpassed the corresponding thresholds. We, to be frank, didn't expect the unit to perform any better here. That said, the results are good enough, and voltage regulation on this rail was amongst the best we have ever measured.

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 is almost half of the limit that the ErP Lot 6 2013 directive sets, so the unit easily meets the corresponding requirements.

Fan RPM, Delta Temperature and 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 39-46°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 custom-made anechoic chamber that is completely covered in specialized soundproofing material (Be Quiet! Noise Absorber Kit) internally. The background noise inside the anechoic chamber was below 30 dBA during testing and the results were obtained with the PSU operating at 39-46°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 in this case was between 27 and 28°C.