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 important for every power supply because it allows for consistent voltage levels despite of 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. 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 and the green line the "Power Good" signal, while the yellow line represents the +12V rail.







Hold-up time is low. Bulk caps are among the most expensive part in a PSU, so manufacturers try to use the smallest possible ones to lower production cost. At least the power ok signal is accurate.

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 VS650's load regulation and efficiency levels under high ambient temperatures. They also show how the fan-speed profile behaves under tough operating conditions.


As expected from such an old platform, load regulation is loose, especially on the +12V rail, which is the most important rail in a PSU. The 3.3V rail also dropped notably under high loads and increased operating temperatures. However, the power supply managed to deliver more than its full power at almost 41 °C despite its 30 °C rating. The fan profile is properly set given the unit's low efficiency readings at high loads, but the fan is noisy because its RPM is high, as it would otherwise not be able to cope with the thermal load.

Light Load Testing

In the following tests, we measure the VS650'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 representing 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 VS650's efficiency at low loads and loads ranging from 10 to 110 percent of its maximum-rated capacity.


The VS650's efficiency numbers are low at both light and normal loads.

5VSB Efficiency

The 5VSB rail is very efficient, which is a pleasant surprise!

Power Consumption in Idle and Standby

Fan RPM, Delta Temperature and Output Noise

The following results were obtained at 32–41 °C ambient.





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