Efficiency

Using the efficiency results from the previous page, we plotted a chart showing the efficiency of the ACP-650FP7 at low loads and at loads equal to 20% -100% of the PSU's maximum-rated load.



The PSU's efficiency is very high, easily placing it above most units with a similar feature set in the charts above; it only loses to the excellent Seasonic Prime Titanium 650, which is also much more expensive.

Efficiency at Low Loads

We measured the efficiency of the ACP-650FP7 at loads much lower than 20% of its maximum-rated load (the lowest load the 80 Plus Standard measures) in these next tests. 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.

A passive operation and very high efficiency under light loads - this is a great PSU for a modern system, which should consumes very little energy in idle.

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 six measurements: one at 100, 250, 550, 1000, and 1500 mA, each, and one with the full load the 5VSB rail can handle.


We would like to see efficiency to be a tad higher (>75%) during the third test, with 0.55 A load. But a 1% difference is nothing to lose sleep over. In an upcoming version of this platform, Andyson should probably update the 5VSB circuit in order for it to be more efficient, especially under higher loads.

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).

Vampire power is very low, but the 5VSB rail's efficiency would be higher at light loads if vampire power with 230V were below 0.1 W.

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 39-46 °C ambient.



A chart that shows the cooling fan's speed (RPMs) and its output noise follows. We measure the fan's noise from a meter away, inside a hemi-anechoic chamber. Background noise inside this hemi-anechoic chamber was below 6.0 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 PSU's entire operating range. The same conditions of the above graph apply to our measurements, but the ambient temperature was in-between 30 °C and 32 °C.



You will hardly see the fan spinning under normal operating temperatures. It will keep its speeds very low even when set to spin - output noise will be a little higher than 6 dBA. Only thanks to our low-noise MIC, which is capable of going down to 5 dBA if needed, were we able to build an accurate noise map for this PSU. We wanted a very quiet PSU, and Aerocool managed to make it happen by using an FDB fan and a very loose fan profile, along with a long semi-passive mode.