Efficiency

Using the efficiency results from the previous page, we plotted a chart showing the efficiency of the SF-750F14EG at low loads and at loads equal to 20%-100% of the PSU's maximum-rated load.



The PSU's efficiency is satisfactory; however, the Seasonic Prime Gold unit (SSR-750GD) easily beats this Super Flower platform at both light and normal loads.

Efficiency at Low Loads

In the next tests, we measured the efficiency of the SF-750F14EG 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 of over 500 W). This is important for settings where the PC is in idle mode with Power Saving turned on.

Efficiency at light loads is absolutely satisfactory. The unit cracked the 80% mark in all cases, which is rather noteworthy for its category.

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 5VSB rail's efficiency is low overall. Regardless of the ATX specification - the 80 PLUS methodology currently doesn't include the 5VSB rail, which has some manufacturers neglect the rail. This is where the new ETA standard offered by Cybenetics is drastically different since it also takes into account this rail's efficiency, along with vampire power.

Power Consumption in Idle & Standby

In the table below, you will find the power consumption and voltage values of all the 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).

With vampire power being as high as it is, the PSU can't achieve 45% efficiency with 0.225 W or less. Super Flower should upgrade the 5VSB circuit in the Leadex platform and should also restrict vampire power to less than 0.1 W with both voltage inputs (115 V and 230 V).

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 output noise follows. We measure the fan's noise from a meter away, inside a hemi-anechoic chamber. Background noise inside the hemi-anechoic chamber was below 16.6 dBA during testing (it is actually much lower but our sound meter's microphone cannot go lower), 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 PSU's entire operating range. The same conditions of the above graph apply to our measurements, but the ambient temperature was between 30 °C and 32 °C.



The fan's passive operation doesn't last very long, even at low ambient temperatures. Although the PSU isn't noisy, the fan's profile could afford to be looser for a much quieter operation.