well..this is a good psu..
their 750w and 550w got a gold medal from hardwaresecret..So you can assume 650w is a good unit to.
750watt review => http://www.hardwaresecrets.com/article/1275
550 watt review=> http://www.hardwaresecrets.com/article/Enermax-NAXN-82+-550-W-Power-Supply-Review/1426
but this is actually not a flawless unit, since ripple and noise is little to high for 12v..even below the maximum allowed..