Efficiency

Using the efficiency results from the previous page, we plotted a chart to show the SS-1050XM2's efficiency at low loads and at loads equal to 10%-110% of the PSU's maximum-rated load.



Efficiency at low loads is higher than with its Platinum sibling obviously tuned to offer higher efficiency at high rather than light loads. The Gold-certified Seasonic unit stays behind most of the competition with normal loads, but compare it to other Gold-certified units in the graph and the actual difference in performance is minimal.

Efficiency at Low Loads

The next tests measure the SS-1050XM2'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.

The unit worked passively in the first two tests, which had it produce absolutely no noise; however, its fan spun up in the next two tests, once ambient temperatures reached 35°C. Most of you would probably like its passive mode to last much longer, especially at such light loads, but Seasonic chose to follow a more conservative and, admittedly, safer route to ensure the unit's reliable operation over the long haul. The SS-1050XM2 was also pretty efficient, surpassing the 80% mark in three out of the four low-load tests we conducted.

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.

5VSB efficiency was good enough and reached nearly 80% during the last test.

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 unit consumes very little power in standby, making 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 35°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 20 dBA during testing, and the results were obtained with the PSU operating at 35°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 temperature was in-between 28°C and 30°C.



As you can see in this graph, passive mode, once elected, doesn't last long, and output noise skyrockets to 40-43 dBA afterward. Seasonic should make the unit's passive operation last longer for those in need of a strong PSU that can operate silently with light loads. Since this is an incredibly efficient PSU, especially at light loads, we believe Seasonic could easily do so, but they, for their own reasons, did not. Seasonic should rethink their strategy on this matter if their intent is to take back a part of the market Super Flower usurped.