Efficiency

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



The Antec unit performed well at both low- and normal loads, achieving a high efficiency score for even a Gold-certified unit. However, the high-end Platinum competition is far more efficient, but we should not forget that such units also cost significantly more.

Efficiency at Low Loads

The next tests measure the TP-750C'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 over 500 W of capacity). This is important for settings where the PC is in idle mode with Power Saving turned on.

Efficiency was pretty high in these tests since the SBRs in the secondary side don't lose a lot of energy at such low loads, and the fan spun at very low speeds despite the high operating temperature (around 35°C-36°C), which kept noise under check.

5VSB Efficiency

The ATX spec 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 achieved decent efficiency that is a little higher than the average, but a reading above 80% would have been nice.

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 was very low. The unit meets the ErP Lot 6 2013 requirements with flying colors.

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 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 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 was in this case between 28°C and 30°C.



At normal ambient temperatures, the fan was very quiet with up to about 400 W. It kicked in hard afterward and was pretty noisy at high load. We think that the fan profile is more aggressive than necessary. Antec and Seasonic apparently meant to make sure the unit lasts for a very long time under even perpetually stressful conditions. Let us also not forget that the number of native cables dramatically restricts airflow to the electrolytic caps in the secondary side.