2019 mbp loud fan when running on external monitor

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Chester McCheeserton Forum Member • Posts: 96
2019 mbp loud fan when running on external monitor

I'm on my 4th adapter after 3 that didn't work – Currently running a USB C to VGA cable.

In activity monitor, WindowServer is hovering between 5 and 20%.

My external monitor is a Lacie 320 from 2008. Resolution is 1600 x 1200.

In System Preferences/Displays it sees the monitor, (lists it by name) and I have selected 'Default for display'. I'm running firefox, Chrome, photoshop, and thunderbird. But none of them are doing anything heavy duty. fans are very audible, though not raging, and machine feels hot.

I see over on Macrumors forum there is a thread that is over 74 pages long on this

I waded through the first 6 pages before my eyes started glossing over. Anybody think purchasing adapter # 5, a USB - C to DVI-D and using the the DVI port instead of the VGA would help?

I've read the suggestions other places about downloading software to disable to turbo boost, running the machine in clamshell mode, or putting it on a stand - none of which I want to do. Is it something to do with trying to use such an old monitor??

garryr Contributing Member • Posts: 554
Re: 2019 mbp loud fan when running on external monitor

Just because a fan speeds up doesn’t necessarily mean theres a problem that needs to be addressed. Your mac is designed to do that so it can run as quietly as possible yet provide sufficient cooling when needed. I don’t know what model you have but mine has over a dozen different sensors monitoring various components inside the computer so it would help to know what component(s) in yours, if any, might be overheating. Without knowing actual temperature values you might be throwing money and adaptors at it needlessly.

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mattspace
mattspace Regular Member • Posts: 492
Re: 2019 mbp loud fan when running on external monitor
1

This is pretty much the normal reported behaviour with (discreet GPU) Macbooks that have external displays connected - It seems to effect AMD desktop GPUs as well - connecting a second monitor causes a BIG rise in power consumption and heat output.

Adaptors etc aren't going to change that. Plugging in the external display powers up the discreet GPU, which isn't normally used to drive the display on the internal screen - IIRC the actual display duty for the built in screen is handled by the iGPU in the CPU, until some 3D graphics, or computational acceleration is required.

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robgendreau Veteran Member • Posts: 7,449
Re: 2019 mbp loud fan when running on external monitor

Ouch.

But I agree, I doubt any adapter, etc is going to make that much of a difference. Maybe getting the body of the MBP cooler.

As proof of that, even people using Sidecar with an iPad have overheating issues. I haven't, but I haven't stressed it much in hot weather.

I've seen reports of Surface Pros overheating in the same circumstances. Small and powerful just means a bunch of heat that's hard to get rid of. Had the same problem with a car on the track, although not THAT powerful....

Maybe there's a workflow solution, since your monitor is so low resolution. Before Sidecar I'd sometimes sync an image I was working on in Lr Classic to my iPad so I could proof it. Took a beat, and didn't work for editing in real time, but got it there. Even the iPhone worked for that, and most any mobile device has more resolution than the old  monitor.

OP Chester McCheeserton Forum Member • Posts: 96
Re: 2019 mbp loud fan when running on external monitor

Okay Hmm Thanks all for the input.

For respondor #1 here are the internal specs: 2.4 GHz 8-Core Intel Core i9 32 GB 2667 MHz DDR4 AMD Radeon Pro 5500M 8 GB
Intel UHD Graphics 630 1536 M

Do you guys think that upgrading to a new monitor with higher resolution would solve it?

Is there a way to turn off the external GPU when I'm doing things that don't need it to keep things cooler and quieter? Even though I paid for it :-x...Dunno I really just expected this to work, returning it to B&H within my 30 days and trading it for an imac is a looming possibility.

mattspace
mattspace Regular Member • Posts: 492
Re: 2019 mbp loud fan when running on external monitor

Chester McCheeserton wrote:

Do you guys think that upgrading to a new monitor with higher resolution would solve it?

Is there a way to turn off the external GPU when I'm doing things that don't need it to keep things cooler and quieter? Even though I paid for it :-x...Dunno I really just expected this to work, returning it to B&H within my 30 days and trading it for an imac is a looming possibility.

Higher resolution is really only going to make the GPU work harder. You could look at an actively-cooled laptop stand.

iMacs are pretty notorious for thermal throttling & fan noise as well, unfortunately.

I can't speak from experience, but it may be that using an eGPU, like an Akido Node (which is properly cooled an should therefore be quieter), and plugging your external displays into it, would prevent the builtin discreet GPU from firing up.

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nicolas guilbert Regular Member • Posts: 271
Re: 2019 mbp loud fan when running on external monitor

i can’t believe this is normal behavior. my old late 2010 MBP with Nvidia discrete GPU was silent most of the time connected to a 27” cinema display.

i read many pages on the topic on macrumours site about the problem on the latest MBP 16”. Some have the problem and others don’t. i didn’t find a clear cut explanation.

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robgendreau Veteran Member • Posts: 7,449
Re: 2019 mbp loud fan when running on external monitor

nicolas guilbert wrote:

i can’t believe this is normal behavior. my old late 2010 MBP with Nvidia discrete GPU was silent most of the time connected to a 27” cinema display.

i read many pages on the topic on macrumours site about the problem on the latest MBP 16”. Some have the problem and others don’t. i didn’t find a clear cut explanation.

Other laptops have problems with this too.

I haven't, but I don't make heavy or more than infrequent use of my 16 with an external monitor. The problem is very extensive. So yes, if it's a dealbreaker than a different machine might be in order.

An iMac's 5120x2880 screen would include more info than the 16's 3072x1920 and the 1600 x 1200, so you might not even need the external where there a switch to iMac. But if the problem is noise, note the iMac fans can spin up too. Just because fans are spinning doesn't mean anything's wrong; there might be some throttling but it is still pretty fast throttled perhaps. Although some report they then do have performance issues.

And yes, the threads and complaints about it are people running some pretty high horse power applications, like Ps and Final Cut and others...they would probably cause even ME to overheat. But Apple did market this as a Pro, so fair criticism.

OP Chester McCheeserton Forum Member • Posts: 96
Re: 2019 mbp loud fan when running on external monitor

Yup I ground thru a fair amount of the endless pages of people complaining about this. It does seem super weird that a small percentage of people chiming in claim they have no problem at all...I think you guys are right that A) the computer is simply doing what it's supposed to do by running the fans that to keep temps down, and B) that changing the adapter won't do anything. still wonder if a new monitor somehow eliminates the issue but that's an expensive test to run.

I tried it in clamshell mode with the lid closed and then fan noise and heat dropped dramatically. So I just ordered a vertical stand and a keyboard. Not totally happy about this solution as I was used to using my laptop open as a second screen. And I basically paid for this retina screen and am now going to not use it much of the time. But for various reasons I do want to try to keep this machine with the dedicated graphics card.

So for anyone considering a new 16 incher - this struggle is real...IF you use an external monitor and don't absolutely need the dedicated GPU for video editing - the 13 inch might make more sense to avoid this problem.

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