Grassmower

this week I put together a new PC with the iGreen 500W as PSU. Reason for the iGreen was the low nois level but this is a disappoinment. Either the PSU is not functioning properly or I forget to connect / do something I should have (not according the U< though) or the PSU is noisier then expected. At this moment the PSU fan is the loudest noise and the PC is in idle (60W consumption total). Anybody out there with advise ?