Mine are pretty loud as well. I'm going to hook them up to my fan controller soon so I can turn it down during light use. They do a good job, but the noise might be a bit unbearable. 1900 RPM and 110 CFM per fan.
Your overclock sounds pretty nice considering your situation! Unfortunately, my computer is stuck in a small alcove, and I don't have room to put it elsewhere, so my temperatures suck.let me know if you have any other questions!