For an OC'ed P4 like that w/XP-90 I'd go with H1BX Panaflo. 57 CFM for 35 dB of noise. Everyone's different, but for me, 35 dB is already kind of annoying, get much higher and I start to tear my hair out. Personally I'd get an XP-120 to cool off a big P4 OC like that, but since you already have the 90, look into the H1BX. Good noise/output ratio on it.