The efficiency of your power supply unit is important because it directly affects you system’s performance and your power bill. The efficiency rating does not reflect the quality or reliability of a PSU. It only reflects the unit’s ability to move power from the wall to your components. The higher a PSU’s efficiency is, the lower the total amount of power it needs to power your system. The MWE Bronze series has an 80 PLUS Bronze efficiency rating, meaning it has a guaranteed typical efficiency of 85%.