When the power supply was working in pair with an APC SmartUPS SC 620, the UPS would report overload at loads of over 365W and 315W (electric mains and batteries, respectively). Switching to the batteries was performed without problems, though. This difference is due to the PSU’s active PFC. It’s clear that it doesn’t cope well with the non-sinusoidal voltage supplied by the UPS’ batteries.
At a load of 550W, the output voltage ripple amounted to 27 millivolts on the +5V rail, to 40 millivolts on the +12V rail, and to 9 millivolts on the +3.3V rail. There’s both low- and high-frequency pulsation here.
The PSU doesn’t have additional independent voltage regulation, yet its cross-load diagram is limited but in a very small part with the voltages going out of the acceptable limits. This occurs when there’s high load on the +5V rail which is unimportant for today’s computer systems. So, this regulation of voltages should be considered good.
The PSU is equipped with a Hong Sheng A1225S12D fan and is rather loud at work. At min load the fan speed is about 1200rpm, which is already not very low. At a load of 270W it is 2000rpm. For comparison, the fan of the above-described PSU from Corsair only reached that speed at full output power (600W). The fans of the Seasonic S-12 and the Zalman PSUs to be described below do not reach that speed at all! So, pretty-looking heatsinks do not guarantee quiet cooling.
The efficiency of this PSU is about 83%. That’s an excellent, even though not record-breaking, result. The PFC device is not that good, the power factor barely reaching 0.97. However, a power factor difference of a few percent doesn’t matter much in practice. To comply with the rather strict requirements of the Energy Star 2007 standard it is only necessary to have a power factor of higher than 0.90 at full load.
So, the HPC-560-A12S is a good power supply with one obvious drawback. It is rather noisy even at minimum load. If this doesn’t scare you, the PSU is going to be a good choice. Otherwise, you should consider alternative products or replace the PSU’s native fan with a slower and quieter one (judging by the low temperature of the exhausted air, there won’t be overheat problems after that).
To be continued!