Mine started quiet and is still quiet. My old G3 iMac sounds like a vacuum cleaner in comparison. There are some programs, like Solitaire Forever, which either don't manage power or resources well. Then the processor goes to 100% and the fans spin to max. Aside from that program, I usually have several programs running at once without any fan noise at all. I am very happy with this machine (17" iMac 1.6 with 1 GB of RAM). HTH