Efficiency

Using the efficiency results from the previous page, we plotted a chart showing efficiency of the G2-1300 at low loads and at loads equal to 20%-110% of the PSU's maximum-rated load.



Efficiency at low loads is good enough for a 1.3 kW unit and well above average at normal loads.

Efficiency at Low Loads

In the next tests, we measured the efficiency of the G2-1300 at loads much lower than 20% of its maximum-rated load (the lowest load that the 80 Plus Standard measures). The loads 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.

Low load results were good for a PSU of the mega-capacity category, but the problem we discovered on all the other Leadex-based platforms we tested so far persists—at such low loads, large AC power consumption deviations can still reach 20-25 W, though the DC load was steady during each of the above tests. Something is going on in the APFC circuit, but whatever it is, it does not help, at least according to our equipment, which is among the best you can buy without breaking the bank.

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 is probably this unit's weak link since its efficiency does not compare to the excellent performance of the other rails. We would like to see a reading over 80% during the last test but barely got 74%. SF will hopefully update this circuit in their next platform.

Power Consumption in Idle & Standby

The table below will give you each rail's power consumption and voltage value (except -12V) in idle mode (when the PSU is 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 increased, but it is still lower than the 0.5 W limit the ErP Lot 6 2013 directive sets.

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°C-47°C ambient.



A chart showing the cooling fan's speed (RPMs) and 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). The background noise inside the anechoic chamber was below 30 dBA during testing and the results were obtained with the PSU operating at 39°C-47°C ambient.



The fan profile is quite relaxed at even over 40°C ambient, but the fan is a speed and noise demon, especially at higher RPMs, yet you can't expect a 1.3 kW unit to be quiet once stressed. Its efficiency would have to be 99% to do so, and we have a very long road ahead of us until we reach that point.