This power supply surprised us. Because of the design used in its primary – half-bridge, i.e., the same one used by old AT power supplies – we were expecting a power supply that would not be able to deliver its rated power and would have an efficiency below 70%.

Seventeam ST-420BKV was able to deliver up to 450 W at 45º C (420 W at 49.5º C), which is an outstanding result. As for its efficiency, it was between 70% and 80%, depending on the load.

On the down side we have the low number of SATA plugs – only two – and no power cable for video cards. So if you want to install more than two SATA devices and/or use a video card that requires an auxiliary PCI Express power connector, you will need to use adapters.

Of course we would prefer buying a power supply with at least 80% efficiency, but if you want a cheap power supply that can truly deliver its rated power and you are building a low-end or mainstream PC, Seventeam ST-420BKV is certainly an option. It survived to our "torture session" without burning!