Seasonic B12 BC B12-BC-650

Medal Count

Seasonic B12 BC-650 is one of the most affordable “Bronze” models from the renowned Taiwanese brand, the leading innovator in the power supply market (only the A12 series with the “White” certificate is cheaper). Active PFC minimizes interference that the PSU feeds back into the mains. Seasonic was the first PSU manufacturer to switch its entire lineup to Active PFC.

Sensible savings

All the necessary components are populated on the input: an EMI filter, a varistor, and a fuse. The high-voltage capacitor is from Taiwanese company Ltec, and the low-voltage ones are from Chinese brands AsiaX and ChengX—thankfully, every single one is a high-temperature 105°C part. The 120 mm sleeve-bearing fan is made by Yate Loon.

Peace and quiet

Fan speed is managed by the smart S2FC — Smart and Silent Fan Control algorithm. At PC idle, the fan spins at an effectively inaudible 600 rpm. As load increases, speed ramps smoothly up to 1600 rpm. And even at maximum load, the main transformer, traditionally the hottest component in a PSU, doesn’t exceed 70°C.

Exceeding the spec

Given the large thermal headroom to critical temperature, the manufacturer backs the PSU with a full 5-year warranty (instead of the typical two to three). There’s power headroom too: independent testing shows the Seasonic B12 BC-650 can handle overloads of up to a whopping 40 percent—an impressive result for a budget PSU. Of course, running the PSU continuously in this mode is strongly discouraged.