Despite the dedicated voltage regulation, the M12D is the only PSU in this review to be not ideal in this test. Its +5V voltage varied greatly depending on load and eventually exceeded the allowable limits.
On the other hand, everything is going to be normal in a real computer. This problem is only observed when there is a high load on the +5V rail, which cannot occur in today’s systems whose components are mostly powered by the +12V rail.
Output Voltage Ripple
The PSU is excellent in this test. The voltage ripple is very low on every rail, excepting the occasional spikes on the +12V one.
Fan Speed Control
The PSU is equipped with a 120x120x25mm Sanyo Denki San Ace 120 fan. Besides the somewhat unusual shape of the impeller, you can see one more interesting thing here:
I don’t mean the open bearing – it is still impossible to lubricate it. And that’s useless because ball bearings are lubricated on the inside and the lubricant does not trickle out. I mean the grooves two of which are partially filled with brown lacquer. Can it be that the fan manufacturer balances each sample of the fan by adding a drop of lacquer on what side of the impeller proves to be lighter due to inaccuracies of manufacturing process? At least, it looks like that.
The fan speed is constant at about 800rpm at loads up to 500W and then begins to grow up. The PSU is very quiet at low and medium loads but the fan becomes audible at 650W and downright loud at near-maximum loads. On the other hand, it is difficult to assemble a computer whose components would be quiet at such a load, so the M12D can be considered a quiet power supply.