Well, let’s get to the tests now. Fortunately, our testbed has the same load capacity of the 12V channels as the TG1300-U6 supports (92A).
Together with an APC SmartUPS SC 620 the PSU worked normally at loads up to 385W (from the mains) and 270W (from the batteries). When the load was higher, the UPS would work for a few seconds and shut down reporting overload. The first number is indicative of a high efficiency of the PSU while the second tells that its active PFC is not quite compatible with UPSes.
The output voltage ripple is higher than the permissible maximum on the +5V rail of the TG1300-U6 (due to short-term spikes). The ITZ1300 has poor results on all the three rails. I’d say Tagan should pay more attention to the quality of the capacitors than to pretty-looking promo stickers.
It’s all right about the cross-load characteristics: the PSUs can work under any load remaining within the 5% voltage deflection. The main voltage, 12V, is almost ideal.
The PSUs are cooled with fans from Top Motor, an 80x80x25mm DF128025BU together with an 80x80x15mm DF128015BU. The consumption current of .45A means that these fans are not going to be quiet.
Rotating at a reasonable speed up to a load of 400W, the fans then quickly reached 3700-4200rpm. They do cool the PSU well – the temperature difference is no higher than 12°C – but the 1300W Tagan is not a quiet PSU. It produces an audible noise even at minimum load.
The PSUs have a high efficiency at medium loads but it worsens towards full load, dropping below 80%.
Thus, the Tagan TG1300-U6 and ITZ1300 are rather ambiguous products. On one hand, they feature neat assembly, a good selection of connectors and excellent stability of the output voltages, but on the other hand, their output voltage ripple is above the limit (especially that of the certified ITZ1300) and they produce too much noise. The wattage of 1300W is about two times as much as a modern PC with a quad-core CPU and a couple of graphics cards needs, so I don’t see any reason why you may want to sacrifice silence for the sake of wattage in this particular case.