Hello,

Well, my son found that there is a program that can control the minimum speed of the fan(s) in a Mac, called smcFanControl, and it does a decent job. If you speed them up, and then turn them down, they take a while to slow back down again. AFAICT, if the temps rise, then the speed ramps up -- this program lets you set the minimums.

For an amazing amount of temperature info, you can use Temperature Monitor -- it reads a total of 13 different temps in my iMac; including things like the memory controller and wireless module, but also the stuff that is more important: heatsink and CPU core temps, GPU, external HD and SMART sensor. You name it, it is there.

cool beans. bookmarked for my next mac debug.

Alternatively, there is also "Fan Control". I prefer its interface and control options over smcFanControl.