CPU throttling less aggressive in Big Sur?

[macagain]

Don't know if it's my imagination or what, but it feels to me like CPU throttling is a little less aggressive in Big Sur. Since upgrading my 2018 6-core i9, I've observed CPU frequency reach as high as 4.36GHz, and temps spike into the 90's a lot more. When on Catalina and before, I don't think I've ever seen the CPU exceed 4.1GHz, and temps rarely exceeded 90F. On the flip side, resting temps also seem to be a few degrees lower that in Catalina and before. (I use iStat Menus, and have either 1 or 2 external 4k's)

Has anyone observed this? Just wondering if it's my imagination, since I "think" thermal throttling is a CPU thing, not an OS thing? Or maybe fan management has improved?

 

[LinkRS]

Howdy macagain,

I have a 2019 16" MacBook Pro with an i9 (purchased in May of 2020), and noticed that fairly regularly the CPU would spike up to 100C with the fans not even coming on. If it stayed at 100C, the fans would kick on, and take it down to like 80C, and then shutoff. I noticed this behavior under both Catalina and Big Sur. Big Sur did not change this for me. Not sure if it is relevant, but I am using istat Menus to monitor temps. I have hard that iStat Menus reported temperature may actually be higher than the actual temps, but have not found any definitive info on that topic. Good luck!

Rich S.

 

[Maddcow]

macgain, there is definitely less thermal (CPU) throttling for me with Big Sur. I'm a musician using my 2019 16" MBP for live performance and I've had a number of experiences with Catalina whereby thermal throttling would cause massive audio and overall system issues e.g. distorted audio, severe slowdown of macOS etc. I recently updated to Big Sur to see if there's an improvement in this area and there definitely is.

I, too, use iStat Menus and closely monitor system temps. The temps have generally remained the same for me with Big Sur but the throttling is significantly less aggressive at those same temps.

 

[Maddcow]

I found a great app yesterday to help monitor when your Mac is thermal throttling. "Hot" is a menu bar app that displays the percentage of CPU currently being used or throttled e.g. 100% means that your machine is using all of the CPU spec, whereas 53% means the machine is only using 53% of its CPU spec, or is being throttled by 47%. It's interesting to see the CPU % decrease in order to get a better idea of the conditions causing the throttling.

HOT

 

[macagain]

I found a great app yesterday to help monitor when your Mac is thermal throttling. "Hot" is a menu bar app that displays the percentage of CPU currently being used or throttled e.g. 100% means that your machine is using all of the CPU spec, whereas 53% means the machine is only using 53% of its CPU spec, or is being throttled by 47%. It's interesting to see the CPU % decrease in order to get a better idea of the conditions causing the throttling.

HOT

Looks like nice little app. However, I've been using it the last couple of hours, and it's been showing 100% all the way, even when temps spike into the 90+ to 100 range for spurts of 20-30 secs. Wonder if it's getting values from the system...

 

[Maddcow]

Perhaps you haven’t had any throttling occur, despite the high temps? What I’m finding is that temperature alone doesn’t appear to cause throttling...I believe there must be a combination of factors that cause it, and I think that Big Sur might have fine-tuned how/when throttling occurs.

The reason I say this is because I’m actually working with Apple engineers at the moment concerning thermal throttling and how this affects live audio production. My testing appears to show that the high temperatures which used to cause instant thermal throttling with Catalina no longer have the same effect with Big Sur. Instead, as you’ve noted, Big Sur appears to be less aggressive in how it handles throttling and how/when this occurs. I was really surprised yesterday when I had my 16” MBP in the direct Australian summer sunlight and it took more than 10 mins for throttling to occur....much longer than the same scenario with Catalina. The throttling also seemed to be more gradual in its onset. However, the same situation as Catalina remains: once throttling has set in, the only way to alleviate it is to reboot or wait a bloody long time!!

In any case, I’m being asked to test quite specific things and if my case is anything to go by, Apple definitely continues to work on the thermal throttling situation.

 

[GumaRodak]

Big Sur, I have experience from gaming and eGPU, while gaming on the 16" with 5600XT in eGPU, the CPU temperature is around 65-75C without FANs blasting, they are around 2800-2900. CPU frequency is constantly above 2.3ghz in intel gadget.

 

[macagain]

Perhaps you haven’t had any throttling occur, despite the high temps? What I’m finding is that temperature alone doesn’t appear to cause throttling...I believe there must be a combination of factors that cause it, and I think that Big Sur might have fine-tuned how/when throttling occurs.

The reason I say this is because I’m actually working with Apple engineers at the moment concerning thermal throttling and how this affects live audio production. My testing appears to show that the high temperatures which used to cause instant thermal throttling with Catalina no longer have the same effect with Big Sur. Instead, as you’ve noted, Big Sur appears to be less aggressive in how it handles throttling and how/when this occurs. I was really surprised yesterday when I had my 16” MBP in the direct Australian summer sunlight and it took more than 10 mins for throttling to occur....much longer than the same scenario with Catalina. The throttling also seemed to be more gradual in its onset. However, the same situation as Catalina remains: once throttling has set in, the only way to alleviate it is to reboot or wait a bloody long time!!

In any case, I’m being asked to test quite specific things and if my case is anything to go by, Apple definitely continues to work on the thermal throttling situation.

I really hope that's the case. After springing for the i9/2.9, I had some buyer's remorse and wished I'd gotten the i7/2.6, or even the 2.2, and saved a few bucks, given all the talk about thermal throttling. If it's really not throttling much or even all, then I'm one happy camper! I've used it a full day now, with my full workload of vscode, eclipse, node, java, music, firefox, chrome, cal, mimestream, message, 2x4k's and it hasn't drop below 100% once.