2018 Macbook Pro Owners: High Fan Activity & Heat Issue Resolved?

Did the 8/28/18 supplemental update fix your high fan activity/heat issue?

  • Yes.

    Votes: 5 11.4%
  • No, but it fixed the Bridge OS kernel panic.

    Votes: 1 2.3%
  • No, but it fixed the speakers/audio crackling.

    Votes: 1 2.3%
  • No, it didn't fix the fan/heat issue.

    Votes: 11 25.0%
  • I wasn't having a fan/heat issue.

    Votes: 26 59.1%

  • Total voters
    44

monstermac77

macrumors regular
Original poster
Nov 21, 2007
176
36
Some 2018 Macbook Pro owners have reported that their machines' fans are audible and run hot even when under low loads (e.g. just watching a Youtube video).

At least one owner, @drdaz, has said that his 2018 Macbook Pro is running "much cooler...with less fan activity" after the most recent supplemental update. I'm hoping to see if this update resolves this issue for 2018 owners. Ideally, someone can do a controlled test, measuring their CPU temp and fan speed while doing the same task before and after the update.

The supplemental update I'm referring to was released on 8/28/18: https://www.macrumors.com/2018/08/28/macos-high-sierra-update-2018-macbook-pro/
 

monstermac77

macrumors regular
Original poster
Nov 21, 2007
176
36
Geekbench results on 2.6Ghz model look good. SC 5214. MC 21939.

Small improvement.
What were your benchmarks before the update? I guess an increase in benchmark would go hand in hand with better thermal management (provided no hardware change), which could mean that the machines are now better at managing low loads with less heat/fan?
 

whateverandever

macrumors 6502a
Nov 8, 2006
776
7
Baltimore
I'm anecdotally getting worse performance playing World of Warcraft today after the update. Fans don't seem to be kicking in as early but it's jumpy gameplay now.
 
Jul 4, 2015
4,488
2,548
Paris
What were your benchmarks before the update? I guess an increase in benchmark would go hand in hand with better thermal management (provided no hardware change), which could mean that the machines are now better at managing low loads with less heat/fan?
About 5% less. But Benchmarks have margin of error anyway.
 

monstermac77

macrumors regular
Original poster
Nov 21, 2007
176
36
About 5% less. But Benchmarks have margin of error anyway.
Yeah, makes sense. I've seen about 3 reports between MacRumors and Reddit saying that the high heat/fan under low loads is "fixed", but based on some of the temperatures I've seen reported it looks like this may not have really been an issue, but rather people expecting their Macbook Pro to be better at dissipating heat than is reasonable.
 

nowarez

macrumors newbie
Aug 26, 2018
2
0
Installed the update but the heat is still there. Watching YT video makes the heat go up to 70-75 degrees. I use iStat Menus, do you reckon I should use System Controlled or manually set fans RPM?
 

1096bimu

macrumors 6502
Nov 7, 2017
319
292
There is no heat/fan issue.
Other than the natural result of you doing more work on a new machine because of moving data/backups to it.
 

Thysanoptera

macrumors 6502a
Jun 12, 2018
795
766
Pittsburgh, PA
Sorry for repost. But two machines, on the left is with update. On the right is without. Both identical in hardware spec.

Running a yes command I.e. max CPU usage. Will post another later this week with istat temps.
Just noticed this. I’d take the one on the right, 5W lower power consumption for the same frequency. That’s a lot. Do you still have both of them? The fans were at max I assume? It is weird, I would expect higher clock for the same TDP, looks like the one on the right has better binned CPU but worse cooling.
 

maflynn

Moderator
Staff member
May 3, 2009
66,778
33,727
Boston
Apple Says Latest macOS Supplemental Update Addresses Audio and Kernel Panic Issues on 2018 MacBook Pro

I don't believe the latest update is addressing the thermal issues, but rather the T2 processor causing Kernel Panics.
When contacted by MacRumors for clarification, Apple said the Supplemental Update improves system stability and reliability across a number of areas, and addresses several issues, including crackling audio and kernel panics. Apple said it recommends all users install the update on their MacBook Pros.
 

SDColorado

macrumors 601
Nov 6, 2011
4,279
4,244
Highlands Ranch, CO
I still get readings like this with certain web pages and earlier today got similar results only sinking my phone via iTunes

Just Safari with one tab open and nothing else.

 

Thysanoptera

macrumors 6502a
Jun 12, 2018
795
766
Pittsburgh, PA
I still get readings like this with certain web pages and earlier today got similar results only sinking my phone via iTunes

Just Safari with one tab open and nothing else.
That's bad, are you sure there is nothing else running? I opened the same page and Safari shows eating 50%, so I guess this is around 4% overall. Fan at idle, 2.2 CPU.
 

SDColorado

macrumors 601
Nov 6, 2011
4,279
4,244
Highlands Ranch, CO
That's bad, are you sure there is nothing else running? I opened the same page and Safari shows eating 50%, so I guess this is around 4% overall. Fan at idle, 2.2 CPU.
Absolutely sure and it only does it randomly. It was doing it a couple of days ago and I was like WTF?? And then they had the supplemental update yesterday and I checked it and temps were in the mid-40’s to low 50’s. Today, back to that.

Earlier today the only thing I had open was iTunes to sync my phone and it did it. Shut down iTunes and temps went down.

Tried syncing my phone the same way probably half a dozen times since then to try to replicate it and I can’t. Dunno. This is on an i9
 

SDColorado

macrumors 601
Nov 6, 2011
4,279
4,244
Highlands Ranch, CO
Next time it happens make a screenshot of the activity monitor, sorted by CPU usage. That's bizarre.
Will do. I should have done that when I had the page open. I left it open about 15 mins to see if it would be ever stop without closing it or see if the temp would ever exceed 100c and shut down. I am still in the return period, so if something bad is going to happen, now would be the time hahaha.

I actually got them to extend the period to 30 days, so still have 3 weeks left.
 

Thysanoptera

macrumors 6502a
Jun 12, 2018
795
766
Pittsburgh, PA
But that page has a huge energy impact and seems to be using almost 105% of CPU?
100% is one virtual core, so it means only 8% total. In my case I get 100% when the page is loading, and if I leave it open it goes down to 10-15%, when scrolling goes to 50%. Maybe you have some Safari extension?
 

SDColorado

macrumors 601
Nov 6, 2011
4,279
4,244
Highlands Ranch, CO
100% is one virtual core, so it means only 8% total. In my case I get 100% when the page is loading, and if I leave it open it goes down to 10-15%, when scrolling goes to 50%. Maybe you have some Safari extension?

Hmm. That was a good thought. I had LastPass (which I was sure wasn't the problem) and 1 Blocker installed. But I disabled them both and I still bounce off 100c. Really not sure what is going on there.
 

Thysanoptera

macrumors 6502a
Jun 12, 2018
795
766
Pittsburgh, PA
Hmm. That was a good thought. I had LastPass (which I was sure wasn't the problem) and 1 Blocker installed. But I disabled them both and I still bounce off 100c. Really not sure what is going on there.
Regardless of what is causing high CPU usage in Safari you should not be hitting 100C with 20% total utilization and fans at max. If it was my machine I'd run some benchmark that loads the full CPU, and compare to the known results. It really looks like something is wrong with thermal paste/heatpipies.
 

SDColorado

macrumors 601
Nov 6, 2011
4,279
4,244
Highlands Ranch, CO
I will try that. Do you happen to know a good one for that purpose? At idle with nothing loaded it sits at around 44C, 0-1% CPU utilization.

Geek Bench will cause it to hit 100C a couple of times, but only for a split second and it cools right back down.
 

Premal212

macrumors regular
Jan 26, 2017
185
69
London UK
Just noticed this. I’d take the one on the right, 5W lower power consumption for the same frequency. That’s a lot. Do you still have both of them? The fans were at max I assume? It is weird, I would expect higher clock for the same TDP, looks like the one on the right has better binned CPU but worse cooling.
Yeah I do. I’ll run a few tests tomorrow evening. Gunna give it back on Saturday. Fans were max yes, it was weird, I thought it was underclocked? Not entirely sure what to think.


I will try that. Do you happen to know a good one for that purpose? At idle with nothing loaded it sits at around 44C, 0-1% CPU utilization.

Geek Bench will cause it to hit 100C a couple of times, but only for a split second and it cools right back down.
Open terminal and copy and paste this -


yes > /dev/null & yes > /dev/null & yes > /dev/null & yes > /dev/null &


It’s known as a yes command. Paste it 4 times, that will max out all your cores, when you’re done testing, type in -

killall yes

That will terminate the yes command.
Let us know how you get on. You’ll know for sure how good your cooling is this way.
 
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