Chosen Solution
I have a fresh install of Big Sur, and at room temperature, doing little more than having Safari open, I get a temperature warning, followed by the laptop going to sleep to cool down. According to the Intel power gadget, the temperature never rises above 55C or so. When it doesn’t sleep, the machine is running super slowly, unless I try to run it in the freezer, in which case it snaps to life. Any ideas? UPDATE: Added photos: When the first warning appears:
And a few minutes later when the second warning appears:
mmm… I’ve seen some strange things! This one I think takes the top spot. Your system is clearly not overheating when you snapped to captures. Time to visit an Apple Store as this is clearly a macOS Big Sur bug! Apple messed up the systems SMC firmware within the updater. Make sure you are clear the system was not having any problems until you upgraded to Big Sur. I would even printout the two screen snaps you have here and you can also hand them this dialog as proof someone with deep knowledge of Mac’s clearly believes this is a firmware failure (one of three we have now discovered in Big Sur here on iFixit).
it sounds like its over heating honestly. are fans running when you power it up?
