Efficiency

Using the results we gathered so far, we plotted a chart showing the PSU's efficiency at low loads and loads ranging from 10 to 110 percent of the maximum-rated capacity.




Efficiency is decent but not competitive for Gold efficiency standards.

10%–110% Load Testing

These tests reveal the PSU's load regulation and efficiency levels under high ambient temperatures and show how the fan-speed profile behaves under harsh operating conditions.


The PSU delivers its full power under tough conditions without any problems. That having been said, I don't recommend pushing it this hard at over 40 °C for prolonged periods of time because its fan will struggle.

Light-Load Testing

In the following tests, we measure the PSU's efficiency at loads significantly lower than 10 percent of the maximum capacity—the lowest load the 80 PLUS standard measures. This is important for when a PC is idle with its power-saving features turned on.


I would like to see more than 70% efficiency with 20 W load and efficiency over 80% with 40 W.

Super Light-Load Testing

We measure the PSU's efficiency with a 10 W load if its maximum power is 500 W or less in the following tests. If the PSU is stronger, we apply 2% of its maximum-rated-capacity load.


The PS-850SP achieves over 60% efficiency with 2% load; however, Intel requires above 70% efficiency with 2% load.

5VSB Efficiency

The 5VSB rail is efficient.

Power Consumption in Idle and Standby

Power consumption in standby is below 0.1 W—I don't have any complaints.