i'm using a Corsair VX 550W PSU(Active PFC) & APC Backup RS 1100 VA UPS(Non Sinewave).On Battery power, the PSU buzzes a little(Very very faint noise,HARDLY audible),but other than that, NO Problems! Have Backup of around 10-15 minutes with my 19" CRT Monitor.I think u can use a similar setup!