When your computer runs too hot
Heat has a huge effect on performance.
My Macbook ran hot. Very hot sometimes. And what happens then is that it sounds like it is getting ready for takeoff. It bothers me, and my office mates (when there were still offices). These tiny fans are loud!
What I did then was something I don’t recommend anyone doing. I installed a tool called Macs Fan Control. Well, it’s a very good tool actually, but not the way I was using it. It shows you the temperature of all major components in your Mac and lets you adjust the speed of your fans. You can run it based on the temperature or run it at a constant RPM. And so I let the fans run at a constant 3700 RPM. Not too slow, but not too fast, just so I barely hear it. The temperature of course goes up. 90 (Degrees Celcius) easy, never higher. It stays there longer because it doesn’t have airflow dissipating that heat from the internals. But. You know, I thought if I only shorten the lifespan by a few years it’s worth the quiet soft pur instead of the constant swooshing sound of a dam releasing pressure.
Time goes by, I forgot all about it.
Now the complaining starts. My computer runs slow. Very slow sometimes, so slow I can’t share my desktop when on Teams. Sometimes compiling Nuxt takes forever. Browsing becomes a chore. Reboot. it’s okay for a bit, then- everything grinds down to a halt again.
What gives?
Well, genius, your nice and quiet experience causes your machine to mellow out. It is way too warm for him to perform so he winds down.
That dip on the left of the graph, that is very telling. It is less than half the speed of the Max Core Frequency that my processor is capable of. (4.0) And after I turned back on the fans, and let it cool down a bit. It stops throttling and the speed goes up again.
Thermal Throttling is a way the CPU tries to lower its temperature by stepping on the breaks and slowing down.
The two tools that made this clear were Intel Power Gadget and pmset.
I believe all Mac users have pmset installed already. PC users can get the same information from Intel Power Gadget easy.
But on a Mac:
- Open up terminal by doing command+space and then type in terminal
- Inside terminal, type:
pmset -g thermlog
It will give you a continuous reading of your processor's status. And in particular, if it is throttled or not, and by how much
No thermal warning levels have been recorded means that everything is fine, the processor is running at full force.
When I turn down the fans. At some point, this happens.
There is a CPU power notify and I now only run at 70 percent of what the processor is capable of inverse relative to the heat of the processor, this number goes down when the temperature goes up. I’ve seen mine go down as far as 40 and CPU temperature was above 100. It is the CPU’s safety mechanism. It tries to lower the temperature by throttling back the frequency on which it operates. It is usually effective, but it means your computer slows down quite a bit.
Not ideal. For neither of us. So you have a higher load (Rendering, Building, etc) temperature goes up substantially (with less fan power) and the CPU speed goes down.
Your system ‘will’ grind to a halt.
What to do? Respect your machine's needs, especially the need for the processor to keep the temperature as low as possible. And learn to live with the fan noise. You chose a machine thinner than a magazine. It will turn on its tiny fans more often because of it.
Put your laptop up a bit, so that air can flow underneath it. Just a little bit will do. Put a pencil underneath width-wise, so it doesn’t wobble.
Intel Power Gadget shows you the current temperature too, the frequency on which the processor and memory are operating, and how much CPU load there is. It runs on all major platforms. On a Mac, together with pmset it can give you a pretty good insight into what is happening inside your machine.
Good luck! And be gentle to your processor.
