The situation:
I work in a very quiet office using MBP Spring 2011 with an i7.
The problem is that when I put an intense but short workload for a few seconds on the CPU the fans spin up heavily, disturbing me and especially my office mates.
I elevated the MAC to get some air flowing under the body but that was not sufficient.
So I found a solution to limit the fan speed, currently limiting it to 3500 by using:
cd /Applications/smcFanControl.app/Contents/Resources
./smc -k F0Mx -w 36b0
./smc -k F1Mx -w 36b0
The question:
How dangerous is doing this?
My current line of thinking is: the cooling is now insufficient for intense long workloads. But if the CPU gets too hot it will just throttle or at worst the MBP might shut down, but nothing worse should happen. Many Laptops have dusty or broken fans and they don't burn out their CPUs either.
Is this a reasonable assumption or am I risking real damage here?
Best Answer
Some quick research says that the i7 processor starts to throttle itself if the temperature range gets too high (around 91C) so you shouldn't have to worry about it provided your CPU temp stays less than that. Mostly the fan speed is trying to keep it comfortable on your lap as best it can - monitor your temperature during one of these "intense sessions" and see if it approaches that threshold - if it doesnt, and stays more on the order of 60C, you're fine as far as short term CPU viability
Research:
https://superuser.com/questions/239230/what-is-a-normal-safe-temperature-for-an-i7-2600k-cpu
http://www.maximumpc.com/forums/viewtopic.php?f=38&t=136130