Performance degrading on sustained workload w/ external monitor? MBP 16"

[x3sphere]

Got my i9 model in today. The fan noise seems comparable to the i7 base model I had before. I also just checked the temperatures with iStat and here are the results...

Running in clamshell mode (attached a screenshot) and I'm seeing ~6W for the GPU. The system is not fully idle right now either, have Chrome open with a dozen or so tabs, plus a VM and VS Code. This is driving a 3440x1440@120Hz display.

However, with the lid open, GPU power instantly shoots up to 20W. I don't see why the power usage should more than double just because you're using the built-in display + an external monitor. I will say for my use case it's not a huge issue since I only use it in clamshell mode when I'm connected to an external display, but hopefully it's something that can be fixed on the software side.

 

[Artemis777]

Got my i9 model in today. The fan noise seems comparable to the i7 base model I had before. I also just checked the temperatures with iStat and here are the results...

Running in clamshell mode (attached a screenshot) and I'm seeing ~6W for the GPU. The system is not fully idle right now either, have Chrome open with a dozen or so tabs, plus a VM and VS Code. This is driving a 3440x1440@120Hz display.

However, with the lid open, GPU power instantly shoots up to 20W. I don't see why the power usage should more than double just because you're using the built-in display + an external monitor. I will say for my use case it's not a huge issue since I only use it in clamshell mode when I'm connected to an external display, but hopefully it's something that can be fixed on the software side.

I had similar results (16inch i9 version), the only thing different is that I'm running a 1080p 120hz display and my gpu power stays up to 18W even with the laptop closed, it gets down to 4W only if I set the monitor to 60hz... this is a shame really..

 

[Idec50]

I'm using the Dell U3818DW (3,840 x 1,600 resolution).

Yeah, it's pretty upsetting, and I would assume that this would also happen on monitors with a lower resolution as well. After some time, intel power gadget shows that the laptop would refuse to use more than 35W of power, even though it can sustain ~55W without the external display.

Are you connecting via USB-C? There are some posts on this thread that indicate the issue might be fixed when using USB-C.

5w was USB-C to USB-C. But the fact is, if I can get 5w and basically 10-15 degrees less by using one connection and not with another, then something is actually wrong.

 

[robvas]

I don't see any evidence of throttling in the original post...

 

[Camarillo Brillo]

I downloaded istat on my new 2.4/32g/5500 so I could check this out, because I too noticed the computer got very warm when I plugged in an external monitor but did not put it into clamshell mode.

Same thing you guys are seeing - with external monitor connected and the laptop open, Radeon is pulling about 18 watts. As soon as I either unplug the external monitor, or close the computer and go into clamshell, Radeon reduces to 4 watts. What I thought was interesting is that even without any external monitor, radeon was pulling <1 watt, and the intel gpu was still at 0. I don't have force radeon GPU on in settings but it looked to me like it was still using the radeon with no external monitor connected.

 

[Idec50]

I downloaded istat on my new 2.4/32g/5500 so I could check this out, because I too noticed the computer got very warm when I plugged in an external monitor but did not put it into clamshell mode.

Same thing you guys are seeing - with external monitor connected and the laptop open, Radeon is pulling about 18 watts. As soon as I either unplug the external monitor, or close the computer and go into clamshell, Radeon reduces to 4 watts. What I thought was interesting is that even without any external monitor, radeon was pulling <1 watt, and the intel gpu was still at 0. I don't have force radeon GPU on in settings but it looked to me like it was still using the radeon with no external monitor connected.

This is also interesting and maybe promising - I spent a long time in tech support chat with apple today, sent screenshots of the istat GPU wattages in clamshell and with both monitors on. They had me boot up in safe mode to see what happens, and I thought it was pretty weird that in safe mode, the radeon gpu stays at a steady ~10 watts, whether the external monitor is connected or not, clamshell or not. So the apple guy and I were speculating that it could be a software issue that could be fixed down the line. Once I got out of safe mode, back to 18/4 watts on the Radeon.

Their next troubleshooting step is to reinstall Catalina, which I suspect won't do anything, but then again, some people are saying they don't have this problem, so who knows, maybe it will help. They told me that if this doesn't do it, they want to get me on with phone support and run it up the ladder. Hopefully I get somewhere.

I'll let you guys know what happens when the Catalina reinstall is done.

I'd recommend that anybody having this issue do what I did, start talking to apple about it, take screenshots of the istat menu showing what's going on, get them logging the calls and complaints and if you think about it, this should protect you in the future when it comes to something going wrong with your computer - you can say hey Apple, look at your records, I started telling you guys about this when I had the computer for 4 days and you told me you were working on fixing it. Could help with late returns/replacements if it turns into some persistent issue. Or if enough people bring it to their attention could lead to a faster fix, if a software fix is possible.

Nice. I hope it works out. I’ll try to do that tomorrow as well. Are you using USB-C?

 

[Camarillo Brillo]

Nice. I hope it works out. I’ll try to do that tomorrow as well. Are you using USB-C?

I’m using HDMI into an RCA USB-C adapter


Catalina reinstall complete, and as I expected, no change, still doing the 18 watt / 4 watt thing. On the plus side, I don’t really plan to use it with an external monitor unless it’s in clamshell mode.

So my next test - hooked up to two monitors in clamshell mode, via two RCA HDMI-USB-C hubs. Radeon pulls about 6 watts, goes up to about 10 if I play a YouTube video on each monitor.

Computer is staying cool and quiet in clamshell.

Now I don’t have fancy monitors, these are just standard 40” HD TVs with HDMI and looks like they’re doing 60hz when I connect them, I don’t know how to change that. But I’ll be working with cheap monitors probably, I’m recording audio, not making movies. On the other hand, it would be nice to know I have full functionality should I decide to plug in a 4K or 5k monitor. Higher resolution monitors will probably make this worse.

But for now I feel mostly satisfied that I can make this work with 1 or maybe 2 external monitors in clamshell mode, with hopes they’ll fix the 18 watt when not in clamshell thing with a software update. As long as I can use it in clamshell as a desktop, as well as standalone, I’ll live with it. Apple knows I’m not happy, in case things get worse in the future...

 

[Idec50]

I’m using HDMI into an RCA USB-C adapter


Catalina reinstall complete, and as I expected, no change, still doing the 18 watt / 4 watt thing. On the plus side, I don’t really plan to use it with an external monitor unless it’s in clamshell mode.

So my next test - hooked up to two monitors in clamshell mode, via two RCA HDMI-USB-C hubs. Radeon pulls about 6 watts, goes up to about 10 if I play a YouTube video on each monitor.

Computer is staying cool and quiet in clamshell.

Now I don’t have fancy monitors, these are just standard 40” HD TVs with HDMI and looks like they’re doing 60hz when I connect them, I don’t know how to change that. But I’ll be working with cheap monitors probably, I’m recording audio, not making movies. On the other hand, it would be nice to know I have full functionality should I decide to plug in a 4K or 5k monitor. Higher resolution monitors will probably make this worse.

But for now I feel mostly satisfied that I can make this work with 1 or maybe 2 external monitors in clamshell mode, with hopes they’ll fix the 18 watt when not in clamshell thing with a software update. As long as I can use it in clamshell as a desktop, as well as standalone, I’ll live with it. Apple knows I’m not happy, in case things get worse in the future...

Well that doesn't really help me but if your name on here is the Zappa song I agree with everything you said.

This is infinitely more boring than that, but I plan to use mine with the screen on in front of an extra-wide monitor. Really nice set-up to use the trackpad and keyboard and keep email and chat open on the less-used laptop screen. Oh **** it, I'm putting on Over-Nite Sensation and pouring a drink.

 

[MrGunnyPT]

Absolutely ridiculous... Look at my print below.

It's using 4GB of the R300M GDDR6

Got my i9 model in today. The fan noise seems comparable to the i7 base model I had before. I also just checked the temperatures with iStat and here are the results...

Running in clamshell mode (attached a screenshot) and I'm seeing ~6W for the GPU. The system is not fully idle right now either, have Chrome open with a dozen or so tabs, plus a VM and VS Code. This is driving a 3440x1440@120Hz display.

However, with the lid open, GPU power instantly shoots up to 20W. I don't see why the power usage should more than double just because you're using the built-in display + an external monitor. I will say for my use case it's not a huge issue since I only use it in clamshell mode when I'm connected to an external display, but hopefully it's something that can be fixed on the software side.

I'm having the exact same issue I use my 16" with my 3440x1440 display and the exact same thing happens.

It's a bit frustrating because I like to keep the work related stuff on the external display and using the laptop display for browsing and twitter.
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I downloaded istat on my new 2.4/32g/5500 so I could check this out, because I too noticed the computer got very warm when I plugged in an external monitor but did not put it into clamshell mode.

Same thing you guys are seeing - with external monitor connected and the laptop open, Radeon is pulling about 18 watts. As soon as I either unplug the external monitor, or close the computer and go into clamshell, Radeon reduces to 4 watts. What I thought was interesting is that even without any external monitor, radeon was pulling <1 watt, and the intel gpu was still at 0. I don't have force radeon GPU on in settings but it looked to me like it was still using the radeon with no external monitor connected.

This is also interesting and maybe promising - I spent a long time in tech support chat with apple today, sent screenshots of the istat GPU wattages in clamshell and with both monitors on. They had me boot up in safe mode to see what happens, and I thought it was pretty weird that in safe mode, the radeon gpu stays at a steady ~10 watts, whether the external monitor is connected or not, clamshell or not. So the apple guy and I were speculating that it could be a software issue that could be fixed down the line. Once I got out of safe mode, back to 18/4 watts on the Radeon.

Their next troubleshooting step is to reinstall Catalina, which I suspect won't do anything, but then again, some people are saying they don't have this problem, so who knows, maybe it will help. They told me that if this doesn't do it, they want to get me on with phone support and run it up the ladder. Hopefully I get somewhere.

I'll let you guys know what happens when the Catalina reinstall is done.

I'd recommend that anybody having this issue do what I did, start talking to apple about it, take screenshots of the istat menu showing what's going on, get them logging the calls and complaints and if you think about it, this should protect you in the future when it comes to something going wrong with your computer - you can say hey Apple, look at your records, I started telling you guys about this when I had the computer for 4 days and you told me you were working on fixing it. Could help with late returns/replacements if it turns into some persistent issue. Or if enough people bring it to their attention could lead to a faster fix, if a software fix is possible.

Would be great if you could see the print screen I have attached showing both Power Gadget and iStat I have the exact same issue as you regardless of the display I connect (either 21:9/16:9 4k or 1080p)

 

[robvas]

Safe mode is probably using different drivers so it's useless for troubleshooting

 

[Camarillo Brillo]

Well that doesn't really help me but if your name on here is the Zappa song I agree with everything you said.

This is infinitely more boring than that, but I plan to use mine with the screen on in front of an extra-wide monitor. Really nice set-up to use the trackpad and keyboard and keep email and chat open on the less-used laptop screen. Oh **** it, I'm putting on Over-Nite Sensation and pouring a drink.

Nice, then put on Roxy and Elsewhere for me

 

[Alex Kurylev]

****! What should I do? I almost always work with an external monitor and I am very upset about this situation. I already passed my MBP 16 with a similar problem and now I don't know what to do! Wait for a solution to the problem or try to take another model and check how it will work with it. This problem has no logic, it is impossible to clearly understand what is the main cause. Will Apple be able to solve this problem in the next updates, or is it much more complicated. The support does not know anything and can not help anything and this is even more frustrating.

 

[robvas]

There is no 'problem'. Any thin and light laptop will have this issue (Dell XPS etc), and actually be worse than the MacBook Pro 16"

Putting a GPU and a 6/8 core CPU in a very small machine will result in heat.

 

[Idec50]

There is no 'problem'. Any thin and light laptop will have this issue (Dell XPS etc), and actually be worse than the MacBook Pro 16"

Putting a GPU and a 6/8 core CPU in a very small machine will result in heat.

Pffft. Then put less power in it or better yet let the user decide how to operate the device they purchased (i.e. lower clock speeds, turn off cores, etc.). And many Windows laptops operate at a higher performance efficiency, maybe because they use Nvidia. I'm peeved that my 2017 MBP outperforms this model.

 

[robvas]

I'm peeved that my 2017 MBP outperforms this model.

You have the benchmarks to back that up?

 

[axlrod]

There is no 'problem'. Any thin and light laptop will have this issue (Dell XPS etc), and actually be worse than the MacBook Pro 16"

Putting a GPU and a 6/8 core CPU in a very small machine will result in heat.

Haha .. there is a problem, the GPU pins at max wattage with external monitors doing nothing, thats not how it is supposed to work, any other MBP will leave the radeon at maybe 5watt at idle..

 

[Artemis777]

is there any news to this problem? It sucks to have the laptop 65 degrees idle when plugged to a monitor...

 

[schertlerbombe]

Hey!
I also stumbled upon this problem recently when i started using my macbook 16“ (base model) with open lid and external monitor. Straight to 18W gpu powerusage when i connect it to my 4k monitor via usb-c.
Tested it with a 2. external monitor: 18,7W with open lid, goes down to 17,5W when i close the lid. (shows the per screen wattage increase should be more like 1-2watt idle instead of 12-14watts)

cpu performance:
no external monitor, max wattage is at around 65-67watt sustained with 3,5-3,6Ghz per core, ~88-90C.
With monitor connected and lid open, cinebench run starts with the same 65-67watts and lowers itself down to ~48watts and ~3,1Ghz, 75C per core after 10 seconds.
Weird thing is, for those 10 seconds the total system power consumption is ~115watts.

Just tried with MacOS 10.15.4, same results.

 

[mrmachine79]

I have the same problem, but on a 2019 15" MBP. I believe it's been around for a long time, but I only just discovered it recently. In my case, the Radeon 560X draws a different amount of power depending on the scaled resolution I've chosen on this LG 27UK850-W 4K monitor. ~18W for "looks like" 2560x1440 and ~12W for both "looks like" 1920x1080 and 3008x1692. Unfortunately, the resolutions with lower power draw are either too big or too small for my eyes.

I want to return this MBP and I know the same problem exists with the 16", but as it has ~12W more cooling capacity and supposedly can therefore sustain higher CPU frequency for longer, I wonder if that will be enough mitigation to avoid the crippling CPU performance I am seeing with external monitor attached and while doing some basic work (Slack, VS Code, browsers, etc.) while also hitting the GPU with a video conference call. It usually stabilises at 1.4GHz (2.3GHz i9) but does drop as low as 800MHz and ~7W reported in Power/PKG via Intel Power Gadget.

Can you people with 16" models confirm if the power draw is consistently ~19W no matter which scaling resolution is chosen for the external display? Or that "looks like 2560x1440" is still drawing the most power with a 27" 4K external?

 

[lobo1978]

You have the benchmarks to back that up?

If you want to cope with i9 heat and prevent throttling you HAVE to disable turbo boost. Here is comparison of performance 9th gen vs 7th gen Intel crap.

I have tested my i9-9880h (8 cores, base clock 2.3 GHz) with turbo boost disabled vs i7-7920hq (4 cores, base clock 3.1 GHz) with turbo boost enabled (MacBook Pro 15" 2017)

Single core i9 = 618 (turbo boost ON = 1077)
Multi core i9 = 4647 (turbo boost ON = 6491)

Single core i7 = 958
Multicore i7 = 3628

 

[Tubamajuba]

If you want to cope with i9 heat and prevent throttling you HAVE to disable turbo boost. Here is comparison of performance 9th gen vs 7th gen Intel crap.

I have tested my i9-9880h (8 cores, base clock 2.3 GHz) with turbo boost disabled vs i7-7920hq (4 cores, base clock 3.1 GHz) with turbo boost enabled (MacBook Pro 15" 2017)

Single core i9 = 618 (turbo boost ON = 1077)
Multi core i9 = 4647 (turbo boost ON = 6491)

Single core i7 = 958
Multicore i7 = 3628

Your comparison is based on the faulty premise that you have to disable turbo boost on the i9. That may be true if you're on the 15 inch model with worse thermals, but the 16 inch can maintain speeds of 3.1 GHz with the 9880H. These chips are designed to run hot, and the fact that boost clocks remain so far above base clocks even at high temps (99C) shows that the CPU is doing fine. The CPU will clock down to prevent damage to itself.

 

[lobo1978]

Your comparison is based on the faulty premise that you have to disable turbo boost on the i9. That may be true if you're on the 15 inch model with worse thermals, but the 16 inch can maintain speeds of 3.1 GHz with the 9880H. These chips are designed to run hot, and the fact that boost clocks remain so far above base clocks even at high temps (99C) shows that the CPU is doing fine. The CPU will clock down to prevent damage to itself.

Yes, you are right - I agree with you.

But I have made this comparison to show that if you want to decrease heat and fan noise, you are limiting CPU to 2015-2016 performance, which is ok for most who are not needing power at the moment and will wait for 1-2 s more for a task to complete. In pro- use, I will not agree for such compromises - allowing for more heat and noise. It is also my current topic of research as I am at this moment testing i9 2.3 GHz 16" against my current i7 2017 15" (3.1 GHz, four cores).

My second point was that Apple heat design is not able to cope with Intel CPU unless they go beyond 10 nm. Even revised 16" is not good enough (in my opinion Apple was forced to build 16" to increase heat envelope).

Please note that size and volume increase (1303 mm3 -> 1426 mm3 = +9.4%) is twice bigger than screen grow (15.4" -> 16" = +3.9%). Turbo boosting current Intel CPUs is just making it worse. I will recommend using CPU with higher base clock and low Turbo/Base clock ratio. In my opinion 7th gen Intel CPUs were the last suitable for MacBook Pro chassis.

I do not think Apple has any patience with Intel anymore. Moreover, Intel is playing CPU game beyond Apple business field (Apple is still a relatively small customer for Intel).

 

[mrmachine79]

The problem is not Intel CPU. It's AMD GPU pulling too much power at idle (20W) with external monitor connected AND Apple's insufficient cooling solution when BOTH CPU AND GPU are under load SIMULTANEOUSLY.

The machine can sustain CPU above rated speed with internal display, or can display high GPU load with low CPU load, but cannot sustain even moderate CPU load with moderate to high GPU load.

Disabling turbo boost does not solve the problem when temps are already high with the CPU 90% IDLE. And if you do something that puts any additional load on the GPU, e.g. run a video chat, the temps will be pushed to max while the CPU is still IDLE. At that point, the CPU will attempt to throttle down DRASTICALLY because the AMD GPU CAN'T throttle down. But throttling down an already 90% IDLE CPU doesn't save much temp, and imposes much more than a 1-2s performance penalty on any heavy tasks. Even with basic work (coding, slack, browsers, etc.) alongside a video chat and an external display connected can result in 1000% kernel task (thermal throttling) and spinning beach balls and freezing up of the whole system for 10 seconds and delayed force trackpad feedback, etc.

 

[alidemirci]

I also have the same issue. I refund my dell p2415q because the fan noise makes me crazy. I called the apple service she advice reset NV RAM and other general things. My Macbook is '16 i9 4gb Graphic https://prnt.sc/salurc

 

[SnackTime]

I am having the same experience with my 16" MBP - i9/5500M 4GB.
With an external monitor connected, running 2560x1440, and in clamshell mode I'm getting 18W Radeon draw.

Disconnecting the monitor and using just the MB's display it drops dramatically. It seems silly that it would need more juice to power fewer pixels at the same (60hz) refresh rate. On its own, it isn't the end of the world.... but coupled with the other dumb problems MacBook's seem to be having it kind of sucks.

Comparatively, I have a Dell XPS 15" with an i9/ GTX 1650 and these issues aren't really present.

For a 'pro' machine I'm not sure I'd expect it to be pinned at max just by taking a zoom call while using a less demanding external monitor. Not even factoring the actual work I'd need it to do!