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.




All SFX units I have evaluated recently belong to higher efficiency categories, so the Ermis 550B doesn't place well in these charts since it is only Bronze (Silver Cybenetics) rated and I had to compare it to Gold and Platinum SFX units. That said, efficiency with a 2% load should exceed 60%.

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.


Because of the low efficiency rating, I didn't push the PSU beyond 40°C. During the "hot" tests, there weren't any problems, but efficiency takes a notable hit at high loads under increased operating temperatures.

Light-Load Testing

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 over 70% efficiency with 20 W load and 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 PSU doesn't exceed the 60% efficiency mark with 2% load.

5VSB Efficiency

The 5VSB rail is inefficient.

Power Consumption in Idle and Standby

Vampire power is high. It should be below 0.1 W with both 115 V and 230 V input.