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jbeyer05

macrumors newbie
Feb 18, 2014
7
3
I wanted to add a quick follow-up to my situation. My situation was that as soon as I plugged in an external monitor, Radeon High Side voltage went up to 20V, temperatures shot up, fans went to 5300, and kernel_task soon throttled the CPU completely.
I visited an independent repair shop who cleaned out the fans and internals of the case. When I plug into an external monitor now, the temperatures rise a bit, and fans get up to 3700, but the temperature remains low enough (150F) that kernel_task doesn't kick in.
So by all means, it still seems like there is a serious issue here if some dust in the fans can cause kernel_task to throttle the CPU to nothing. And I'm not thrilled that the fans need to run at 3700 as soon as I plug in an external monitor. But if you haven't cleaned out the fans and internals of the case, give that a try.
 
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mihirdelirious

macrumors member
Mar 15, 2021
90
559
I wanted to add a quick follow-up to my situation. My situation was that as soon as I plugged in an external monitor, Radeon High Side voltage went up to 20V, temperatures shot up, fans went to 5300, and kernel_task soon throttled the CPU completely.
I visited an independent repair shop who cleaned out the fans and internals of the case. When I plug into an external monitor now, the temperatures rise a bit, and fans get up to 3700, but the temperature remains low enough (150F) that kernel_task doesn't kick in.
So by all means, it still seems like there is a serious issue here if some dust in the fans can cause kernel_task to throttle the CPU to nothing. And I'm not thrilled that the fans need to run at 3700 as soon as I plug in an external monitor. But if you haven't cleaned out the fans and internals of the case, give that a try.
There are 3 different issues at play here:
1) VRM power throttling -> This is the main issue with the 16" MBP due to no cooling mechanism on VRM chips. This is why we actually face the severe performance drop/throttling even on a cleaned 16" MBP.

2) Dust/Lint build-up inside -> can cause CPU/GPU thermal throttling. There's no alternative to opening the Mac and cleaning the dust every few months. Apple does make it incredibly hard to open most Macs nowadays and they don't tell customers that computers should be cleaned for dust/lint regularly either.

3) dGPU pulling 18W with external display -> I think we can conclude at this point that the 18W draw is a software/driver problem. Note: The 18W issue by itself should not cause any problems apart from fan noise. However, it does trigger throttling from 1) and/or 2) --> makes the throttling quicker & more severe. Apple denied this for almost 2 years now and are quietly patching it in Monterey.

Out of these, 2) can be alleviated by regular cleaning. 3) is something Apple is quietly fixing with Monterey. 1) is something that power/pro users will still face under workloads that use both CPU & GPU together *regardless of external display* (added in edit).
->There's a very slight chance that silicon level optimization/tweaking could improve the VRM power throttling, maybe by adjusting the temperatures-power supply curve if that's possible?. Who knows... maybe Apple will patch it quietly in 2023 with MacOS 14.
 

maik_is_here

macrumors member
Nov 4, 2019
34
14
There are 3 different issues at play here:
1) VRM power throttling -> This is the main issue with the 16" MBP due to no cooling mechanism on VRM chips. This is why we actually face the severe performance drop/throttling even on a cleaned 16" MBP.

2) Dust/Lint build-up inside -> can cause CPU/GPU thermal throttling. There's no alternative to opening the Mac and cleaning the dust every few months. Apple does make it incredibly hard to open most Macs nowadays and they don't tell customers that computers should be cleaned for dust/lint regularly either.

3) dGPU pulling 18W with external display -> I think we can conclude at this point that the 18W draw is a software/driver problem. Note: The 18W issue by itself should not cause any problems apart from fan noise. However, it does trigger throttling from 1) and/or 2) --> makes the throttling quicker & more severe. Apple denied this for almost 2 years now and are quietly patching it in Monterey.

Out of these, 2) can be alleviated by regular cleaning. 3) is something Apple is quietly fixing with Monterey. 1) is something that power/pro users will still face under workloads that use both CPU & GPU together *regardless of external display* (added in edit).
->There's a very slight chance that silicon level optimization/tweaking could improve the VRM power throttling, maybe by adjusting the temperatures-power supply curve if that's possible?. Who knows... maybe Apple will patch it quietly in 2023 with MacOS 14.
Fantastic and crisp write-up, thank you!

To add one detail for completeness' sake: The VRM Mod can effectively mitigate 1) and can be done together with 2).
I asked my trusted repair shop to look at the reddit post and they did it for me. The great thing is that it is reversible.

Result:
No more throttling. even with external monitor it stays constantly above 3Ghz. Fans are high though.
What is fascinating is that that due to the lack of throttling, under full load it draws more than 100W now. With every hour of full load (i.e. meetings, sharing stuff etc) it loses about 5% battery.

 
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mihirdelirious

macrumors member
Mar 15, 2021
90
559
Thanks a lot.
I intentionally omitted the VRM mod for a reason. I also tried the VRM mod a few weeks back but it made the bottom plate too hot to use on my lap; it's very effective for those who use the MBP exclusively on a desk. But it might not be a good solution for the users looking to use it as a laptop.
 

jbeyer05

macrumors newbie
Feb 18, 2014
7
3
There are 3 different issues at play here:
1) VRM power throttling -> This is the main issue with the 16" MBP due to no cooling mechanism on VRM chips. This is why we actually face the severe performance drop/throttling even on a cleaned 16" MBP.

2) Dust/Lint build-up inside -> can cause CPU/GPU thermal throttling. There's no alternative to opening the Mac and cleaning the dust every few months. Apple does make it incredibly hard to open most Macs nowadays and they don't tell customers that computers should be cleaned for dust/lint regularly either.

3) dGPU pulling 18W with external display -> I think we can conclude at this point that the 18W draw is a software/driver problem. Note: The 18W issue by itself should not cause any problems apart from fan noise. However, it does trigger throttling from 1) and/or 2) --> makes the throttling quicker & more severe. Apple denied this for almost 2 years now and are quietly patching it in Monterey.

Out of these, 2) can be alleviated by regular cleaning. 3) is something Apple is quietly fixing with Monterey. 1) is something that power/pro users will still face under workloads that use both CPU & GPU together *regardless of external display* (added in edit).
->There's a very slight chance that silicon level optimization/tweaking could improve the VRM power throttling, maybe by adjusting the temperatures-power supply curve if that's possible?. Who knows... maybe Apple will patch it quietly in 2023 with MacOS 14.

Thanks mihirdelirious. I did not mean to gloss over 1 and 3. I'm in full agreement that those are serious issues that Apple should address.
 

electronino

macrumors newbie
Sep 16, 2021
7
24
Giving an update regarding my adventure with a $4000 hairdryer.

I did data collection exercise with the engineering team and got the response back today.

It works as expected.

How silly of me to expect not to have fans blow at full speed with one external monitor connected.

My comments how older MacBooks and 5600 GPU does not do this, were ignored.

It is clear Apple will do everything they can to not let me exchange the laptop for a different model.

I however won't accept $4000 laptop to run like a hairdryer when attached to an external monitor.

I asked for an official copy of the response "it works as expected". My next steps will be writing to Tim Cook directly in order to get to the bottom of this. If all of this gets deflected, my next steps would be to contact local consumer protection agencies and the media.
 
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GumaRodak

macrumors 6502a
Mar 14, 2015
583
362
i am with you, even if i dont have the issue, i do not use external monitor now.
If there is a software fix, they have to fix it
 
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kaans

macrumors regular
Nov 17, 2014
239
67
mihirdelirious's analysis is gold, thank you

It seems Monterey is a good fix tho, I don't see the point in delivering useless performance, if you've overclocked/underclocked CPU/GPU's before, sometimes if you just reduce the clock/voltage 10% - the peak average heat reduces from 90C's to 60-70C's - I'm hoping that if I always keep the low power mode on, it'll just be a better laptop

The downside is using the machine for a bit more than a year now, with all that heat, at 246 cycles my battery is at 83% - seems pretty low :(

Edit: If there wasn't scrolling issues reported at beta 7, I was going to upgrade myself and for the first time use a beta Apple OS
 

JosepPont

macrumors regular
Oct 25, 2019
240
197
Albaida, Valencian Country
Hi guys.

A year ago a selled my 16" MBP because the heat issue and waiting to see how the M1 perform. Six months ago I bought a desktop wintel machine that is for gamming, heavy load and renders (32 RAM, RTX3090, i9 10900K). After a year and seeing that M1 isn't for me (yet) and seeing that, aparently, the heat issue will be fixed in Monterrey, I'm thinking about purchase for a 16" intel MBP.

My work will be mixed between windows apps and Mac apps, I'll use Parallels to run W10. Also I use Blender but only few models "eat" lot of RAM so I think my sweet spot is 32GB of RAM. I know that is better run Blender with the desktop machine but the f**** windows OS crash when I'm working with very heavy models that need lot of RAM (more than 32) and my the last MBP (that is in the sgnature) could do it, slowly but the machine was working.

Summarizing: I need a Non-Desktop Mac to run VM and do some heavy Blender 3D models (one every two or three months).

What do you recommend?

  • i7 or i9? is there any diference with the VRM heat issue?

  • 5300 or 5500 (4 or 8 GB)?
One last thing, in Spain there is an store that will have the students offer until october 23th with a 12% discount and a 0% finance during 36 months. Is itpossible if I wait until the (suposed) Mac event on october 12 will disapear the possibility to purchase the Intel MBP?

Another option is buy it in ebay but here in Europe is plenty of fakes and scammers. Purchase it in ebay USA I see good options but is risky because of customs taxes


Thank you very much!!
 

kaans

macrumors regular
Nov 17, 2014
239
67
I think either go cheap, get the 5300 or go 5600 as it already was capable of driving itself with lower power

I'm in the same wagon as you are, it's an expensive sacrifice, but I'll keep this 16" Macbook just for VM's and the once every 2-3 month windows builds

Otherwise can't wait to buy one of the new 16" Macbooks with the new screen technologies

It seems some people are renting heavy cloud machines for these tasks, and hibernating them when not in use, I guess it's the ultimate solution, but in your case, a 3D render on a cloud vm ... challenging
 
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mihirdelirious

macrumors member
Mar 15, 2021
90
559
Hi guys.

A year ago a selled my 16" MBP because the heat issue and waiting to see how the M1 perform. Six months ago I bought a desktop wintel machine that is for gamming, heavy load and renders (32 RAM, RTX3090, i9 10900K). After a year and seeing that M1 isn't for me (yet) and seeing that, aparently, the heat issue will be fixed in Monterrey, I'm thinking about purchase for a 16" intel MBP.

My work will be mixed between windows apps and Mac apps, I'll use Parallels to run W10. Also I use Blender but only few models "eat" lot of RAM so I think my sweet spot is 32GB of RAM. I know that is better run Blender with the desktop machine but the f**** windows OS crash when I'm working with very heavy models that need lot of RAM (more than 32) and my the last MBP (that is in the sgnature) could do it, slowly but the machine was working.

Summarizing: I need a Non-Desktop Mac to run VM and do some heavy Blender 3D models (one every two or three months).

What do you recommend?

  • i7 or i9? is there any diference with the VRM heat issue?

  • 5300 or 5500 (4 or 8 GB)?
One last thing, in Spain there is an store that will have the students offer until october 23th with a 12% discount and a 0% finance during 36 months. Is itpossible if I wait until the (suposed) Mac event on october 12 will disapear the possibility to purchase the Intel MBP?

Another option is buy it in ebay but here in Europe is plenty of fakes and scammers. Purchase it in ebay USA I see good options but is risky because of customs taxes


Thank you very much!!

I recommend buying a 13" Intel MBP (with 32GB RAM & i7 processor) along with an eGPU like the Sonnet Puck 5500XT/5700. The Sonnet Puck eGPU supplies 60W of charging which should be perfect for a 13" MBP, and it's quite enough for you to carry in place of the laptop charger/dongles anywhere. You'll get far better performance and no throttling this way. The 13" Intel MBP will also be a fair bit cheaper than a 16" MBP.

I would avoid the 16 inch MBP like the black plague. It's simply not worth the hassle. Considering your use case of Blender for 3D modeling, you'll hit VRM power throttling after 20 mins of heavy CPU & GPU workload (even without an external display). I use Wwise (the audio/music middleware) with Unity & Unreal engine. I keep hitting VRM throttling after 20-30 mins of usage. Please don't fall for YouTubers who show you fancy benchmark numbers and random video game frame rates. It's not real world usage, and those 'influencers' will never really speak against Apple for obvious reasons. Personally, I bought a Sonnet 5500 XT eGPU to use with my 16" MBP (base model with 1TB SSD), and it's the only way to make the 16" MBP work for me.

Edit: I checked Apple's website and they still officially sell 13" Intel MacBook Pros. So you should be able to get a custom configuration with i7, 32GB RAM & 1TB SSD too. Also, you could buy a different eGPU now or in the future if you require.
 

kaans

macrumors regular
Nov 17, 2014
239
67
This might be an obvious question (I didn't read the last 150 pages), but is there a guide on how to determine which throttling we're hitting

As an example, how do you determine you're hitting the VRM throttling?
 

JosepPont

macrumors regular
Oct 25, 2019
240
197
Albaida, Valencian Country
I recommend buying a 13" Intel MBP (with 32GB RAM & i7 processor) along with an eGPU like the Sonnet Puck 5500XT/5700. The Sonnet Puck eGPU supplies 60W of charging which should be perfect for a 13" MBP, and it's quite enough for you to carry in place of the laptop charger/dongles anywhere. You'll get far better performance and no throttling this way. The 13" Intel MBP will also be a fair bit cheaper than a 16" MBP.

I would avoid the 16 inch MBP like the black plague. It's simply not worth the hassle. Considering your use case of Blender for 3D modeling, you'll hit VRM power throttling after 20 mins of heavy CPU & GPU workload (even without an external display). I use Wwise (the audio/music middleware) with Unity & Unreal engine. I keep hitting VRM throttling after 20-30 mins of usage. Please don't fall for YouTubers who show you fancy benchmark numbers and random video game frame rates. It's not real world usage, and those 'influencers' will never really speak against Apple for obvious reasons. Personally, I bought a Sonnet 5500 XT eGPU to use with my 16" MBP (base model with 1TB SSD), and it's the only way to make the 16" MBP work for me.

Edit: I checked Apple's website and they still officially sell 13" Intel MacBook Pros. So you should be able to get a custom configuration with i7, 32GB RAM & 1TB SSD too. Also, you could buy a different eGPU now or in the future if you require.
Yes, that is a very good point!! Thanks for the suggestion!!
 

Appledoesnotlisten

macrumors 6502a
Original poster
Dec 2, 2017
505
208

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mihirdelirious

macrumors member
Mar 15, 2021
90
559
This might be an obvious question (I didn't read the last 150 pages), but is there a guide on how to determine which throttling we're hitting

As an example, how do you determine you're hitting the VRM throttling?
Note: The CPU is rated ~45W at base clock & the 5300/5500 GPUs are rated ~50W. So their total rated power draw is ~95W when running together!

In macOS Catalina/BigSur, run CineBench (30 or 45 minutes test):
1) Use iStat to monitor the total power draw of your system under heavy load for more than 20-30 minutes without external monitor. The 16" MBP will max out around 55-60W of power draw after 20-30 mins. The CPU will settle around 2.6 GHz for me.
2) Run the same test with an external monitor connected for 20-30 mins again. Here, GPU draws 18W+. That leaves less than 40W for CPU (since the total power draw includes GPU, screen, keyboard, thunderbolt bus etc.).

->Since GPU & CPU are on separate dies/chips with 2 fans and connected heat pipes. In theory, 55W being pulled by 2 separate chips should give us far better heat dissipation than 1 single chip. So if it were the CPU thermally throttling beyond 55W, it'd still draw around 55W when an external display is connected (& total power draw would go around ~75-80W). However, this is not the case.

CineBench is a pure CPU test, nothing to do with GPU. IF you introduce anything that uses the dGPU, the CPU's power draw drops significantly as the GPU starts being prioritised by the 16" MBP (kernel_task throttles CPU & CPU locks to 800 MHz ). Here the CPU is not being fed enough power (it's far below 45W).

It's not possible for these CPUs to be thermally throttling if they're running at a mere 800 MHz with fans running at full.
You could also monitor the temperatures in addition to this, and they'd not indicate any sort of overheating.
 

Appledoesnotlisten

macrumors 6502a
Original poster
Dec 2, 2017
505
208
aah I see you have an i9. I have i7, thats why my macbook is cooler.
Should not make a difference because the 2 extra cores are not generating heat when not in use... And 5500 is not that different from 5300. So maybe my time will come with the next update?
 

david0128

macrumors regular
Aug 10, 2021
119
144
I’ve got the (£3,800) i9 MBP with the fan issue when connected to two 5k ultrafine monitors. Apple’s suggestion was to sell the current MBP on eBay and buy a replacement MBP with the £800 additional graphics option (I think it’s the 5600?). Erm… no.

Anyhow, on a long term basis I knew that I needed an intel processor to run VMs for work. I therefore purchased the Intel 2018 Mac mini [absolute base model] a few weeks ago (£1,000). Even though it doesn’t support it in the spec sheet, it is running the two 5k monitors at 60hz (it will only do this if you have the monitors plugged in during boot and nothing else on the usb-c type sockets). I was thrilled to find that it would run these external monitors with a processor temperature of under 50 degrees. Parallels Windows machines boot up a little slower on the Mac mini (like 5-10 seconds slower), but they run just as quickly and the fans barely ramp up. Learning point for me is that you shouldn’t discount having a basic desktop machine and maybe a cheaper laptop for travel.

Earlier points on cleaning the fans are important though. It makes a difference, but doesn’t solve the issue. The only issue is that you need to do it every three months.
 
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PeterJP

macrumors 65816
Feb 2, 2012
1,136
896
Leuven, Belgium
Is there a tutorial somewhere on how to open the machine & clean the fans? I've done it plenty of times on other machines, but the MBP is a different story from your average Windows machine. I mainly need to know what screw drivers to use.
 

jomanji

macrumors newbie
Sep 27, 2021
2
1
Using 60Hertz on both monitors. What is freesync / vrr?
Free sync / VRR is variable refresh rate. For me if I used Variable refresh rate the temps would be as bad as before and if I set it to strictly 60 the temps and fan noise were much better. It’s worth double checking since in my case Variable was set by default for some reason.
 
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Stanislas_S

macrumors newbie
Sep 27, 2021
1
3
Just installed Monterey on i9-5500 and the temps are as bad as they were. Has not helped my machine :(
hi! i have the same model and problem has gone (radeon high side is about 5-10W)
1. check that you have installed all updates to beta 7
2. it works better in "low battery mode" - try to activate it (System settings - battery - power saving mode)
 
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