The new PSUs feature the HeatGuard function which keeps the built-in 120mm fan running for 30 to 60 seconds after shutdown to dissipate remaining heat, have active PFC (Power Factor Correction), and utilize a multiple protection circuitry.The low-end NAXN 80+ power supplies use two +12V rails but lack 80Plus certification, they are available in 350W, 450W and 550W versions for $44, $49 and $64, respectively. The 500W and 600W models on the other hand do have 80Plus certification, they will retail for $74 and $84, respectively.
The NAXN 82+ lineup offers 80Plus Bronze, the 750W model offers two +12V rails and will cost $134, while the 850W sibling offers four +12V rails but pricing is still unknown.
Source: TC Mag