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 PSU characteristic since it allows for constant voltage levels even with changes in load.

5VSB Regulation

Hold-up Time

Hold-up time represents the amount of time, usually measured in milliseconds, a PSU can maintain output regulations as defined by the ATX specification without input power. 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 and the green line is the "Power Good" signal, while the yellow line represents the +12V rail.

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.

10-110% Load Testing

These tests reveal the SDA2-650'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 SDA2-650's efficiency at loads significantly lower than 10 percent of its 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.

Efficiency

Using the results that we gathered so far, we plotted a chart showing the SDA2-650's efficiency at low loads and loads ranging from 10 to 110 percent of its maximum-rated capacity.


Efficiency with light loads is high enough. With normal loads, the unit falls behind the competition, though. As you can see in the graph above, FSP's other platform, used in the EVGA 650 GM, performs much better.

5VSB Efficiency

The 5VSB regulator needs upgrades for improved efficiency. FSP has highly efficient 5VSB regulator circuits, which has me wonder why its engineers used this one.

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.