Test Setup

Primary Rails Load Regulation

The following charts show the voltage values of the main rails, recorded over a range from 60 W to the maximum specified load, and the deviation (in percent) for the same load range. Tight load regulation is an important characteristic for power supplies since it allows for constant voltage levels despite changes in load.

5VSB Regulation

Hold-up Time

Hold-up time represents for how long, usually in milliseconds, a PSU can maintain output regulations as defined by the ATX specification without input power. Put simply, hold-up time is the amount of time the system can continue to run without shutting down or rebooting during a power interruption. In the following screenshots, the blue line is the mains signal, the green line the "Power Good" signal, and the yellow line the +12V rail.






Hold-up time is low. At least the power ok signal is accurate, though well below the 16 ms the ATX specification requires.

Inrush Current

Inrush current, or switch-on surge, refers to the maximum, instantaneous input current drawn by an electrical device when it is first turned on. Large enough inrush current can cause the tripping of circuit breakers and fuses and may also damage switches, relays, and bridge rectifiers. As a result, the lower the inrush current of a PSU right as it is turned on, the better.


With 230 V input, inrush current is quite high.

10-110% Load Testing

These tests reveal the SF750's load regulation and efficiency levels under high ambient temperatures. They also show how the fan-speed profile behaves under tough operating conditions.

Light Load Testing

In the following tests, we measure the SF750's efficiency at loads significantly lower than 10 percent of its maximum capacity (the lowest load the 80 PLUS standard measures). This is representative of when a PC is idle with its power-saving features turned on.

Efficiency

Using the results we gathered so far, we plotted a chart showing the SF750's efficiency at low loads and loads ranging from 10 to 110 percent of its maximum-rated capacity.

This is a very efficient platform under both light and normal loads.

5VSB Efficiency

This is one of the most efficient 5VSB rails we have seen so far.

Power Consumption in Idle and Standby

Fan RPM, Delta Temperature and Output Noise

The following results were obtained at 37–47 °C ambient.





The following results were obtained at 30–32 °C ambient.