Both units correspond to the ATX12V 1.3 standard. It means that, unlike the previous models, they must provide a load current of 18 amperes or more on the +12V rail. The maximum load currents of the PSUs are the same, the top model differing from the junior one only in the allowable total load power.
The stability of the output voltages is good. Of course, these PSUs cannot rival models with auxiliary voltage regulators, but they do perform well in their own class.
The output voltage ripple is the same with both models (at the same load, of course). So, the oscillogram above shows the pulsation of the top model, taken under this model’s maximum allowable load of 350W. The voltage swing is somewhat bigger than we have seen with the models of the GTF series (particularly, you can now see minor spikes at the moments the inverter’s transistors are switched), but this parameter anyway complies with the requirements of the standard.
Both PSU models display similar-shaped dependencies of the fan speed on the load (the regulators are integrated directly into the PSU’s circuit, so they are identical in both PSUs), but the curve of the junior model is somewhat shifted to the left. The last fact may be due to a random discrepancy in the ratings of the elements employed. The PSUs work silently only under small loads. When the load is high, the fans are quick to speed up to their full capacity, i.e. a little above 1200rpm. The air stream from the 12cm blades creates some perceptible noise at such a speed. Curiously enough, the manufacturer of the fans – the fans are Yate Loon D12BM-12 – rates them for 1700rpm, but I don’t have a reason to mistrust the showings of my tachometer.
The power and efficiency factors of the two units are identical, too. Like with the above-described GTF series units, the power factor is higher than that of units without PFC, yet it doesn’t exceed 0.8. The efficiency isn’t high, either. It is 71% at the max load (the ATX12V 1.3 standard is stricter than version 1.2 here and demands an efficiency of no less than 70% at full load).
So, these power supplies are going to serve well in a low-end or midrange computer thanks to their increased load capacity on the +12V rail. Yet, if you need a high current on this very rail, it would be wise for you to consider PSUs of the new version of the standard, ATX12V 2.0, which are discussed later in this review. ATX12V 1.3 units occupy a rather narrow market niche, by the way. On the one hand, many low-end computers are quite satisfied with ATX12V 1.2 PSUs (see the above-described ATX-350GTF, for example). But on the other hand, ATX12V 2.0 models are the best choice for a modern computer. So, you may want to consider 1.3 units as an upgrade to your current system (if your older PSU has crashed or something) that consumes much power from the +5V rail since ATX12V 2.0 power supplies have a low allowable load on this rail and are not quite suited for +5V-oriented computers.
The drawbacks of the reviewed two PSUs from FSP Group are, like with the GTF series, the relatively low efficiency and the loud fan that accelerates to high speeds under high loads.