Several manufacturers release higher capacity power supplies within the same series by simply replacing the secondary rectifiers with more powerful models. Fortunately this is not the case with BFG MX-680: the manufacturer replaces ALL components (PFC transistors, switching transistors and secondary rectifiers) with more powerful models compared to the 550 W product. This explains why we could pull up to 785 W from it.

If you are building a PC that is going to pull up to 544 W (80% of its labeled capacity), this power supply may be an option. At full load, however, efficiency drops below the 80% mark and we also had a huge ripple problem with the -12 V output when we pulled between 272 W and 408 W from it.

Another issue was that the auxiliary fan didn’t kick in automatically: we had to manually rotate it with the tip of a pencil in order to turn in on. This also happened with the 550 W model we reviewed.

A very important thing to keep in mind if you buy this unit: warranty. You have to register your power supply with BFG within 30 days of its purchase, otherwise you will only get a two-year warranty instead of the full five-year one. This is really tricky, as most users do not register their products with the manufacturer.

It comes with a somewhat attractive price tag – USD 130 –, but we think that there are better options on the market, like Seventeam ST-750Z-AF, which is cheaper, has a higher labeled wattage, also has a modular cabling system and provides a better performance.