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Flyview

macrumors member
Original poster
Mar 20, 2018
68
20
Hey everyone,

I discovered something on this hot July day! My late 2013 15" MacBook Pro throttles the CPU and makes the computer extremely slow (taking seconds just to register a mouse click) when the battery temperature reaches 39c.

It does this by ramping up CPU usage of kernel_task, taking away CPU from everything else. At first I didn't know what was going on because I've had the CPU and GPU much hotter (closer to 90c) than it was today without throttling. After carefully looking through the temps and going into and out of the throttling zone a few times, I noticed that the trigger seems to be the battery temperature (battery sensor 1) reaching 39c.

I was inside a hot vehicle at around 32c inside temp, running an external 4k monitor so the dedicated GPU was active. Even inside with some AC at 25c ambient temperature, no external monitor, the battery sensor is sitting at 32c without anything intensive running. That means there is only 6c wiggle room for it to go up before throttling!

Can anyone confirm? Is there a way to adjust at what temperature this happens?

P.S. I discovered TG Pro today for fan control. I had been using Macs Fan Control but TG Pro is better because you can set your own fan temperature ramps and set it based on multiple sensors as opposed to just one!
 
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