Performance

I was of course interested in how noisy the VGA Power would prove to be at work. It is cooled with two 40mm fans built into its front panel (there is a dust filter in front of the fans; it cannot be removed, but you can clean it from the outside with a vacuum cleaner when necessary). The speed of the fans is automatically varied depending on the temperature of the heatsink with the diode packs.

Unfortunately, the fans don’t have an integrated velocity sensor while our optical tachometer isn’t very correct with objects of so small a size, so I had to limit myself to measuring the voltage of the fans. As you see, it does depend on the PSU load (on its temperature, to be exact) and is rather high, over 7V, even at the min load.

As for my subjective impressions, the VGA Power is noisy. Its sound can be heard even at small loads. At loads from 150 to 200W the VGA Power can well become the noisiest component in your computer. The position and the type of the fans only make the things worse. They are at the front panel of the system case, so the latter doesn’t suppress their noise at all. Small and working at a high speed, the fans produce a characteristic high-frequency hiss that rises above the rest of the system noises.

On the other hand, if you use graphics cards with standard cooling solutions, the fans of the VGA Power won’t be distinctly heard as their noise is similar in loudness and spectrum. But if you use quiet coolers from Zalman, Arctic Cooling or other manufacturers, you will hardly like the VGA Power.

Otherwise the PSU leaves a nice impression. The output voltage is almost ideally stable, varying from 12.07 to 11.96V at loads of 50 to 300W. This is not surprising if you remember that the problems with stability of the output voltages of ordinary ATX power supplies are all due to the fact that such PSUs have to be seeking a balance between their multiple output voltages. Here, there is only one output voltage.

I had apprehensions that the VGA Power might be too hot and dangerous for the nearby optical drive. The diagram above shows the temperature of the hottest spot on the cover of the VGA Power case (if was not installed in the computer, but was lying on a desk; the air temperature in the room was about 22°C). If your system case permits, it is better to leave one bay free above the VGA Power because even though its cover is not used for cooling (besides an air gap there is a thick insulating pad between the cover and the heatsinks), its temperature is over 40°C at max load. So if the VGA Power is under high load, and the neighboring DVD-drive is working with a disc (like when you are playing a game that is regularly reads its data from the disc), the drive may feel not quite well. Modern high-speed optical drives heat up a lot just in cramped cases and heating them up from below won’t make things any better…

The output voltage ripple at full load was about 90 millivolts (73 millivolts of a high-frequency, 285kHz pulsation and the rest is a low-frequency, 100Hz pulsation) which easily fits in the acceptable range (120 millivolts).

The efficiency of this power supply is a little below 85% at high loads. I had expected a better result considering the simpler design in comparison with standard PSUs (particularly the lack of a group regulation choke which is rather hot at work) and the high pulse-width modulation frequency. The power factor is quite standard for a PSU with active power factor correction and reached 0.99.