Efficiency

Using the efficiency results from the previous page, we plotted a chart to show the efficiency of the Snow Silent-1050 at low loads and at loads equal to 20%-100% of the PSU's maximum-rated load.



The Snow Silent unit uses lower efficiency fets in the APFC converter than its sibling, the SS-1050XP3, yet it somehow manages to register higher overall efficiency with both light and normal loads. Seasonic obviously implemented some minor changes we failed to spot in our internal analysis to decrease energy losses. The Snow Silent is an incredibly efficient unit as it placed second with normal loads; however, it only placed in the middle of the pack with light loads.

Efficiency at Low Loads

The next tests measure the Snow Silent-1050's efficiency with loads much lower than 20% of the 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 at good levels with light loads; however, we have seen Gold and Platinum units with a similar capacity achieve significantly better results here. Seasonic obviously cared more about the performance with normal loads and made a point of tuning this PSU accordingly.

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.

Efficiency on the 5VSB rail was pretty good since the PSU managed to crack the 80% mark in the last test, and readings in the first three were also high enough.

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 on its 5VSB rail).

The unit consumes very little energy in standby 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 38°C-45°C ambient.



A chart that shows the cooling fan's speed (RPMs) and its output noise follows. We measure the amount of noise the fan produces from one 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 at an ambient temperature in-between 38°C-45°C.



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 temperature was in-between 28°C and 30°C.



The PSU runs in passive mode at up to 500 W under normal conditions, and the fan engages for a limited time afterward to shut down for a short period once temperatures drop. Output noise increases to annoyingly loud levels with 850-900 W.