Corsair TX550M & TX750M Power Supply Review @ OCC
 

The DC voltage load regulation is generally good, with a worst case -3.6% on the +3.3V rail. The noise/ripple values, on the other hand, could be better although it manages to stay within the limits set down by the ATX12V specification, but only just. The efficiency/power factor correction of the TX550M is on a par with other power supplies in this class, as tested by the OCC power supply methodology.

http://www.overclockersclub.com/revi...tx550m_tx750m/