BFG ES-800 isn’t the best product available on the market, but it is also not the worse. If you decide to buy this product, you need to make sure that your serial number starts with 0835 or greater, otherwise you will have a huge electrical noise problem. Also, if you decide to buy it, you must register within 30 days of buying it, otherwise you will lose the lifetime warranty provided by BFG and get only a louse 1-year warranty.
If you have a unit with production batch lower than 0835 (most likely 0804), contact BFG and ask them to replace your unit, because your model is completely flawed.
But even the “fixed” version of this power supply presents high noise levels when delivering 800 W. This shows how having only Japanese capacitors may mean nothing.
BFG ES-800 presents a high efficiency between 84% and 85% if you pull up to 60% of its labeled capacity (i.e., up to 480 W). Pulling 80% from its maximum wattage efficiency dropped to 82.4%, still above 80%. At full load, however, efficiency dropped to 79.1%.
Having so many “ifs” and costing USD 190, we can’t recommend this power supply, even though if you bought one from the right batch you should not face more problems, as most people won’t pull even close to 800 W. Currently there are several other better options on the market (e.g., Corsair HX850W costs the same thing, doesn’t have the same issues and presents a far higher efficiency).