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P90Xfit

macrumors regular
Original poster
Feb 7, 2009
129
0
What should I set my fans to in smcfanctrol? Is it ok to even mess with the fans? Would I mess up the system or something? Will I burn up the fans? Also, what is on OK temp for my UBMBP? What is the hottest it could get? Should I dig in and replace the thermal paste?
 
At roughly 105C, the CPU will start to throttle itself in attempt to cool down and keep from self-destructing. Somewhere beyond that, a function called THERMTRIP will go off, and the CPU will quit executing. At this point, the hardware controllers are also supposed to yank power from the CPU. The GPU has a fairly similar setup in place. Keep in mind though, that the temp sensor you see is an in-socket sensor, and will read lower than the actual die temperature that governs this sort of thing (that doesn't report an actual temperature though, so it isn't used). It may be offset in the firmware, but there is really no way to know.

smcFanControl will not damage your machine, or burn out the fans or anything like that. Personally, I find tiny fans like the ones in the MBP incredibly annoying, and would prefer not to hear them. The machine doesn't get dangerously hot unless it's under load, in which case I usually bump them up to around 3500-4500 rpm. You can "season to taste". Don't go after the thermal paste unless you are having problems. Especially if you have never done thermal paste application before. Most people get it wrong on their first try, and the MBP isn't a good machine to practice on, the heatsink is an incredible pain in the ass to get out.
 
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