Output Voltage Stability
Notwithstanding its dedicated voltage regulation, the APS-750C performs worse in this test than the CFT-600-14CS. The three main voltages are within a 3% deflection under typical loads, though, and none of them deflects more than 4% under any allowable load, so this PSU honestly gives you each watt written in its specs.
Output Voltage Ripple
There are short spikes of voltage on the +5V rail a little above the allowable limit, but you shouldn’t worry about them much. Otherwise, the PSU complies with the ATX12V requirements regarding the output voltage ripple.
The PSU has a 140mm fan made by Globe Fan. About one quarter of its impeller is covered with a transparent plate that drives the air into the back part of the case for better ventilation.
The fan starts out at a speed of 900 RPM but the PSU is not really quiet. The fan is as fast as 1000 RPM at a load of 300 watts. Thus, the APS-750C is average in terms of noisiness. It will satisfy most users, especially at low loads, but people who want complete silence may be disappointed with it.
Together with my APC SmartUPS SC 620 this power supply worked at loads up to 360 watts when powered by the mains. But when the pair switched to the batteries, the UPS would shut down in a couple of seconds even at a load of 300 watts.
Efficiency and Power Factor
The efficiency is about 86% at the maximum, but quickly falls below 80% at low loads.
The standby source copes with its job well: its output voltage is no lower than 5.0 volts under maximum load.
The Chieftec A135 Series APS-750C is just a good power supply. It is stable and quiet (but not exactly silent) but has poor compatibility with UPSes (at least, UPSes that have a non-sinusoid output voltage). You should not confuse it with the A135 series models that have the letter S at the end of the model name because it is based on a completely different platform and has different characteristics (even though the difference is not large in terms of practical applications). Comparing the APS-750C with the CFT-750-14C, I cannot easily name the better product. The former is somewhat quieter but the latter works well with UPSes. Both models have rather short cables: you may find this to be a real problem if you are assembling your computer in a large system case.