Efficiency

Using the efficiency results from the previous page, we plotted a chart that shows the G2-750's efficiency at low loads and loads equal to 20% -110% of the PSU's maximum-rated load.



The unit did pretty well with low loads, beating many units with the same characteristics and capacity, including a few Platinum ones. The G2-750 couldn't quite deliver such stellar performance with normal loads, although it still scored a pretty good position in our corresponding graph.

Efficiency at Low Loads

In the next tests, we measured the efficiency of the G2-750 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 a PSU with a capacity over 500 W). This is important for settings where the PC is in idle mode with Power Saving turned on.

The unit completed the whole test session in those tests were we only applied low loads in passive mode. Its registered efficiency was pretty good overall; however, it could have been better had the unit only achieved a reading over 80% in the 40 W load test.

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 Achilles' heel of the new Leadex platform looks to be its 5VSB circuit because it is inefficient, which definitely doesn't go with its other top-notch specifications. The rail never managed to hit or even get close to the 80% mark, not even during the full load test.

Power Consumption in Idle & Standby

In the table below, you will find the power consumption and 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 pretty low and easily meets the 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 37°C-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 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 30 dBA during testing, and the results were obtained with the PSU operating at 37°C-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 temperature was in-between 28°C and 30°C.



The PSU operated in fanless mode at up to about 370-380 W, which kept its noise output to a minimum. Afterward, the fan spun at very low speeds with low loads, producing a relevant amount with only 500-550 W and more load to move any and all heat out of the PSU's enclosure.