Efficiency
Efficiency is calculated by dividing the delivered DC figure from the amount of AC required at the wall. In essence, what is the wattage cost of converting AC to the DC supply used by PCs. Stepping down a grade or two in componentry means the Rosewill cannot, justifiably, mix it with the 80 PLUS Platinum supplies out there.
Our testing shows that it does however have enough efficiency to warrant an 80 PLUS Bronze certification.