Efficiency

Using the efficiency results from the previous page, we plotted a chart showing efficiency of the SF-1300F14MG at low loads and at loads equal to 20%-110% of the PSU's maximum-rated load.



Efficiency at low loads is very high for such a high capacity PSU, although a bit lower than the Platinum 1 kW Leadex unit at normal loads, which is as expected. The Leadex Gold 1300 W PSU is, all in all, very efficient at both low and normal loads, thanks to its cutting-edge platform; SF's changes were obviously effective.

Efficiency at Low Loads

In the next tests, we measured the efficiency of the SF-1300F14MG 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 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.

At low loads, we again noticed the same behavior all Leadex platforms have so far exhibited during these tests, since we measured pretty large AC power consumption deviations of up to 20-25 W, although DC load was kept steady in each test. Only our sophisticated software suite through which we control and monitor our loads allowed us to calculate the PSU's actual efficiency in these tests, which was especially high for its category.

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 isn't that efficient. Considering the PSU's overall performance, we expected more here. SF should re-design this circuit to make it a worthy match for this platform, and increase the rail's output by another 10 W.

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).

This PSU consumes less than 0.5 W in standby, which makes it ErP Lot 6 2013 compliant.

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-47°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-47°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 was in this case between 28°C and 30°C.



The PSU mostly operated in fanless mode at up to about 600 W, although noise output increased dramatically once the fan fully engaged. The fan operated at high RPM with over 1kW load, which produced enough noise to annoy most users. VGA- and CPU coolers will, however, fully cover up the noise this PSU's fan produces if either is cooled by an audible solution.