The cross-load diagram is almost ideal with this PSU series as we have had a chance to see with the two previous models. The maximum deflection from the nominal value is 3% while the +12V voltage diagram is a solid green field.
The output voltage ripple is stronger now, yet within the norm: up to 30 milliseconds on the +5V and +3.3V rails and up to 110 millivolts on the +12V rail.
The PSU uses a Yate Loon D14BH-12 fan remarked as TT-1425B (the D14BM-12 fans of the two previous PSUs were renamed likewise). Yate Loon declares a rated speed of 2800rpm for this fan while Thermaltake says 2300rpm. Judging by my measurements, Thermaltake is nearer to the truth.
And again, the fan speed remains at about 1200rpm under loads below 300W, then grows up quickly up to 2100rpm under loads up to 600W (the PSU temperature gets stabilized at that as the diagram shows), and then it is the PSU temperature that begins to grow. The latter amounts to an alarming 19°C (to remind you, this is the difference of the air temperatures at the input and output of the PSU) and the meaning of this strange regulation remains a mystery.
The Toughpower 850 AP is somewhat noisier than its lower-wattage predecessors. It is especially noticeable under low loads because the min fan speed has increased from 1000 to 1200rpm. It is only in certain parts of the diagram that it surpasses its predecessors by beginning to increase the speed later, but anyway, you shouldn’t expect the more powerful PSU to be quieter than its lower-wattage mates in this particular case.
The PSU notches an efficiency of 87% at a load of over 400W. That’s an excellent result. The power factor is 0.95 on average, increasing a little towards higher loads.
So, the Toughpower 850 AP is a good high-wattage PSU with superb electric parameters and capable of powering any modern configuration except for exotic components like thermoelectric Peltier elements. It’s got two drawbacks. First, the manufacturer should have been more attentive to the PSU specs and specify which line powers which connectors since the different +12V lines are not equivalent to each other in terms of allowable load. Second, this PSU is not quiet. It is average or even somewhat worse than average in this respect and is noisier than its lower-wattage mates due to the use of a faster fan.