i'm looking forward to getting my iMac i5 27" this Sunday. I doubt even if I have "grumbling" noise, I'll even notice. This is only because I have endured years of my G5 Quad's fans going strong at 3000+ RPM even at idle. Only recently have I need to run the machine at reduced to not get into thermal runaway. I think the iMac will be like buttery whispers compared to my howling G5 Quad...