Constantly warm 2015 MBP 13" on Big Sur

[howardc64]

Been this way since first going on Big Sur a few months ago. MBP usage is as follows

- Always on adapter, battery fully charged
- Close screen when not in use, presumably sleeping with PowerNap

MBP seems quite warm every time I pick it up to use. Will actually cool down when used or left to sleep without closing the screen. SMC and PRAM reset would help for a couple of days and back to always warm behavior.

Activity Monitor shows kernel_task and WindowServer as big CPU consumers (see attached along with MBP info and Battery preference on power adapter)

I guess workaround for now just to leave the screen open when not in use and let it sleep on its own.

 

[ewu]

I suggest that you reinstall Mac OS Mojave.

 

[mj_]

When did you last reboot your Mac? It may sound like a cliché but many problems can be solved by simply rebooting your computer.

 

[howardc64]

Thanks for the suggestions.

On back to Mojave. Going backwards has its challenges. I'll probably live with power down during the night with no use before that.

On last shutdown, I probably shutdown every couple of weeks. I'll give it another try.

This morning MBP was warm even though screen was open and manually put to sleep the night before. Thus, screen probably have nothing to do with it.

I do have Time Machine running to Time Capsule and it runs periodically. But that has never been the issue before in prior OSX. Perhaps I'll shut it off temporary to see if culprit.

 

[sgtaylor5]

I've used MacsFanControl at 3500 rpm (stock, unmanaged speed is about 1250 rpm), and that helped when I was on Big Sur for a month (now back to Mojave).

... even then, I would see temps rise to the 60's and 70's C for a short period, which never happened on Mojave, which is why I downgraded.

 

[TonyM42]

Same model here - no problems with Big Sur / overheating but I do always shut down overnight.

 

[Macdctr]

I have the spec'd 2015 13-inch model and have not experienced any issues since upgrading to Big Sur. One thing I did recently was refresh the thermal paste on the CPU and heatsink just because the laptop was over 5 years old. Just something to think about...

 

[darngooddesign]

You need something that displays temps and fan speeds. This is what TG Pro says my Mid 2014 13" MBP on BS is doing at idle. The bottom of mine always feels warm, because it has an Intel chip. The M1BP doesn't even spin its fan at idle.

 

[howardc64]

Thanks for all the replies. Thermal paste replaced with Arctic Silver a couple of years ago + fan cleaned. Had no heating problems with Catalina before Big Sur.

Reboot seems to have cured this for a day now. Will see how long it last haha.

BTW, have always used smcFanControl to have base fan speed @2k (silent). 2015 MBP 13 default fan speed is low and lazy compared to late 13-14 MBP 13s so 2k RPM fan keeps it cooler from default. Another area to watch in case Big Sur messed with smcFanControl (which restarts on new login). Anyway, when MBP is cold, prob <= 40c, when warm to touch after long sleep, shows 65c.

 

[bernuli]

2 suggestions for better sleep:

1) Disable power nap. I've always done that out of habit.

2) Unplug the power adapter when done using. Possibly first suggestion will override the need for this suggestion.

 

[howardc64]

2 suggestions for better sleep:

1) Disable power nap. I've always done that out of habit.

2) Unplug the power adapter when done using. Possibly first suggestion will override the need for this suggestion.

Good idea on Disable power nap. Will do so if/when gets warm again to confirm cause/effect. Thanks!

Do have icloud, 8 mail accounts (yahoo, icloud, outlook, I'm the online world admin for extended family haha), Time Machine to Time Capsule so power nap could be culprit.

 

[nothingtoseehere]

I had a warm laptop, and considerable battery drain overnight, with my 13“ MBP 2015 on Mojave. I disabled power nap and changed hibernatemode as well as the standbydelay time via Terminal. That helped.

Here is an instruction: https://www.howtogeek.com/260478/how-to-choose-when-your-mac-hibernates-or-enters-standby/

 

[howardc64]

Back to constant warm lappy a couple of days after power cycling. Tested no PowerNap/AC adapter sleep last night, ice cold lappy this morning.

Wife has a Late 2013 Retina 13" on Catalina. Powernap off and constantly on AC adapter + CinemaDisplay. Ice cold when sleeping with just about all the same config (smcFanControl, Time Machine to Time Capsule, multiple email accounts etc) But on Catalina of course where my 2015 also had no warming problems.

Looks like its disconnect magsafe at every lid closing on Big Sur until Apple find a fix.

 

[startergo]

I had the same issue. Then I used
0xbb/gpu-switch: gpu-switch is an application that allows to switch between the graphic cards of dual-GPU Macbook Pro models (github.com)
to switch to IGPU. Problem solved.

 

[bernuli]

Back to constant warm lappy a couple of days after power cycling. Tested no PowerNap/AC adapter sleep last night, ice cold lappy this morning.

Wife has a Late 2013 Retina 13" on Catalina. Powernap off and constantly on AC adapter + CinemaDisplay. Ice cold when sleeping with just about all the same config (smcFanControl, Time Machine to Time Capsule, multiple email accounts etc) But on Catalina of course where my 2015 also had no warming problems.

Looks like its disconnect magsafe at every lid closing on Big Sur until Apple find a fix.

Maybe that not a bad idea anyway.

But another question. Try leaving the computer with the caps lock on. Later, when you think the computer is sleeping, is the caps lock light on or off?

 

[howardc64]

UPDATE

Been disconnecting magsafe when sleeping worked fine. Updated to 11.3 a few days ago, problem seems to be gone now so Apple probably fixed something. However, magsafe disconnected sleep feels ice cold while connected sleep feels closer to room temperature. But definitely way better than before when it would always be warm.

 

[Jamalien]

How is this an issue? If you leave it plugged in it’s going to do background sync tasks whilst sleeping. Without the fans going, this will result in a lukewarm machine when you wake it up. Big Sur may do more frequent background tasks when plugged in.

There is nothing for Apple to fix. This is normal behaviour…

 

[bernuli]

How is this an issue? If you leave it plugged in it’s going to do background sync tasks whilst sleeping. Without the fans going, this will result in a lukewarm machine when you wake it up. Big Sur may do more frequent background tasks when plugged in.

There is nothing for Apple to fix. This is normal behaviour…

Apple did fix something. My mini under 10.15 would be at room temperature when sleeping, however it would often kernel panic while waking. 11.2 fixed the kernel panic but the machine would be above ambient temperature while sleeping. So I figured Apple fixed the panic by not allowing deep sleep. Not a huge deal.

11.3 is back to normal. Mini is now at room temp when sleeping, which means it is actually sleeping well. And no more kernel panic on wake.

Good fix from Apple!

I still think unplugging laptop while not in use a good idea. Gives the battery some gentle exercise, though this may not matter with the recent OS changes to battery management. The new normal might be to leave plugged in.

 

[howardc64]

Found the culprit. It was Microsoft Edge (latest version) Was eating 100% CPU all the time. Edge has a feature to check website security called Microsoft Defender Smartscreen that was causing this. Turn it off and CPU load < 1% but eventually crept back up to 100%. Now giving up on edge and going back to chrome.