The PSU has a total output power of 650W and can yield up to 624W across its +12V rail divided into four “virtual” output lines, each rated for 18A (216W).
I found no problems with the PSU when it was working at full load.
The output voltage ripple is within the permissible limits at every of the PSU’s three main output rails.
The +12V voltage is just ideal, deflecting by no more than 1% from the nominal value at any load, from 50W to 650W. The +5V and +3.3V voltages vary more, but only exceed a 3% deflection at near-maximum loads. None of the voltages exceeds the permissible deflection of 5%.
As for the noise factor, the power supply is indeed silent at low loads, its fan rotating at less than 800rpm. However, the fan accelerates rapidly at loads higher than 200W, reaching 1000rpm (which is roughly the limit of quiet operation) at a load of about 270W. Besides the hiss of the airflow, the fan is buzzing audibly.
Thus, this PSU can stand no comparison with the Enermax MODU82+. The Enermax is quieter through the entire range of loads. And while the Toughpower QFan can be called comfortable at loads below 250W, its fan speed grows so rapidly thereafter that the operating PSU becomes surely noisy. Of course, it is far quieter than the wailing fan of the SuperTalent Atomic Juice PS-700, yet there is no talking about “Extremely Quiet” as promised by the manufacturer.
Comparing the Toughpower QFan with its closest relatives in Thermaltake’s product line-up, namely Purepower RX and ordinary Toughpower, the QFan is quieter at low loads only. When working at high loads, these PSUs produce about the same amount of noise.
The QFan is no record-breaker in terms of efficiency, but its result is good: a peak efficiency of 86% and an efficiency of 84% at full load. I should note again that these results are no different from the efficiency of the Purepower RX and Toughpower PSUs.
Summing everything up, I can’t really say that the Thermaltake Toughpower QFan is a poor product. On the contrary, it delivers the declared electrical parameters, offers a good selection of connectors, and boasts problem-free operation. The problem is that the QFan is actually no different from the Purepower RX and Toughpower series which have been selling for long and reviewed regularly although it claims to be exceptional. Its fan design is even questionable in terms of noise reduction (the aerodynamic noise of the air passing through the side slits is rather going to worsen this parameter whereas the leakage of the air sideways lowers the effective performance of the fan) and is presented by the manufacturer in a totally misleading way: the laws of physics and the common sense suggest that the air is going out of the PSU but the picture at the Thermaltake’s website shows exactly the opposite. Added to that, the fan of our sample of the PSU would buzz audibly at a speed of 1000rpm and higher. This may have been a defect of the particular sample, though.
Thus, the Toughpower QFan is quieter than any other model of the Toughpower and Purepower RX series at low loads and comparable to them at medium and high loads. It cannot offer serious competition to truly quiet power supplies such as the above-discussed Enermax MODU82+.