Intel Macs have something called the SMC (System Management Chip, or something like that) which among other things, monitors all the temperature sensors and manages the fan speed.
There are apps (on macOS) that can tweak the fan speed. SMCfanControl is one, Macs Fan Control is another; there may be others still. A decent such app will allow you to raise the fan speed above what the system would have picked, but never set it lower, to ensure that at least the builtin cooling specs are met. If you're going to do a parallel compile or something else that maxes your CPU, setting the fan speed to max before that starts will likely let you run a bit faster longer before getting throttled to control the temperature. On Linux, if you google for mac linux smc fan you should see some alternatives. I've never run Linux on bare metal on a Mac (in a VM, yes), so I've never had any reason to try any of those, let alone recommend any particular one. > On Jul 6, 2023, at 00:25, James <[email protected]> wrote: > > I've been a long time macports user. > > My mid 2011 iMac27 is pegged at High Sierra. I can't build recent mythtv and > other woes, after a fail flirt with opencore I installed linux. > > I asked on the various user forums, but got only well intentioned naive > answers. > > Is fan control done by hardware? > > If so why: https://github.com/Hipuranyhou/macfand > > I did a faily heavy shotcut render. At the point I chickened out cpu fan was > at minimum (1200 rpm) and core were at 55C > > Do I need to do sw control of the fans? (Chickened out means I dialed the > fans to FSD and temp came down to 40C) > > James > >
