There are a lot of features the Thermaltake Silent PurePower PSU boasts, the most noticeable being the dual fans with the gold grills. As stated above, the power supply that Thermaltake sent us today is the 420W version, and one of the better features of the power supply is what Thermaltake calls Active PFC. Active PFC gives the ability for the power supply to run at its maximum threshold. Some of the cheaper PSUs on the market will have severe drops in power giving system instability. This is where Active PFC comes in - it helps to prevent these power drops and attempts to keep the power stable 95-99% of the time.