Mac Pro's Fan (Mid-2012) extremely high speed sometimes. Help!

The Mac Pro fans are controlled mostly by software. Their speed is set based on measured temperatures from a number of sensors inside the cabinet.

If the software is still running, fans at top speed indicate some components are reporting very high temperatures.

If the software has crashed, Hardware takes over and runs the fans at top speed to avoid a meltdown.

If the CPU detects its own temperatures are too high, it can cause sudden shutdown without notice.

Your machine is not crazy. It is operating exactly as designed. High temperatures have been detected, and it is running the fans to unload that heat.

Try to check your Mac Pro with Apple Hardware Test if it pass first.

Then reset SMC.

-- kaz-k

Someone had the same behavior last week, and just installing and using SmcFanControl wrote new profiles for fan behavior - seemed like the old plist was corrupt or needed to be deleted. Can't hurt and might help.

Utility gives you the option to set multiple fan profiles and have a different "base" floor rpm.

Then using Temperature Monitor already? so you and we can see the thermal readings.

There is a near identical post today complaining about a 123*C temperature from one of the sensors and that is a more serious concern.

Same BS on my machine. But I tried to restart with PRAM reset maybe 1569845651354 times. Nothing hepls. It goes crazy no matter what - got fresh system on other HDD - same BS. Already beign with my machine at Apple store - they did hardware test - it shows everything 100%. I feel like i will end up with throwing it out from my balcony. Fall down 46 storeys will definetly helps these fans to stop 🙂

You should try and put on a different frame of mind. Do the same thing over and over and expect different results? that is wishful thinking.

I don't know the rest of the story but for me, when PRAM reset didn't work I used a different keyboard. Worked. Might have been majic but more likely the kb or USB cable.

Keyboard? I could try... Maybe I should go buy 5 new iPads - sure it could hepl a lot 🙂 I think somethings wrong with one of the recents MLion updates - It was never happen before last 2 updates. I was rendering super hard things last summer and it was superhot in my room - fan speed was just above lovest a liilte bit - now it goes crazy regardless of everything. I even try to remove extra HDD's - nothing helps.

Situation like that clearly show how useless is Apple techsupport in case of something really serious. These guys can help you with transferring your music and photos from iPad to iMac but everything else - go figure yourself they not just don't know - they don't care at all. I had some Adobe troubles a week ago - and these guys spend 30 minutes with me helping me to manually step-by-step fix some "deep" software settings, which basically saves my 3 days work and 5 grands. Apple is not even close to that level of service. What they can do at max it is just say "You probably need a logic board replacement" (forgetting to mention that it could be cheaper to buy a new machine sometimes 🙂).

I expect there is an SMC problem. When this happens, reset the SMC:

Intel-based Macs: Resetting the System Management Controller (SMC)