MacBook 16-inch Fan Noise

Nthompson,

great point!

I found this comment on the Gearslutz forum made sense to me-

***connecting external 4K monitors forces everything to run on the AMD GPU. In activity monitor the GPU utilization (could be found in the window menu) changes from internal to the Radeon. iStat Menus shows a power consumption of 18-20W for the 'Radeon Highside'.

- when the AMD Radeon completely idles and everything runs on the Intel GPU, it consumes 0.15 to 0.2W. 

The AMD GPU sits together with the Intel CPU on the same heatpipe. They share the same thermal budget. Those 20W the Radeon consumes, heat up the CPU and will force it to throttle down sooner. And/or will ramp up fan speed earlier and stronger.

I dont know if it makes a huge difference if you have the 5300M or the 5500M with 4/8GB on your 16" macbook. Theoretically the 5300M and 4GB should consume less power. 

My opinion: Apple should drastically reduce the power consumption of the AMD GPU. Sacrificing 20W on a laptop for doing nothing more than moving the locator in your (LOGIC PRO X ) DAW is absolutely unacceptable. *****

heres the link :

https://www.gearslutz.com/board/music-computers/1287355-boom-new-16-macbook-pro-8tb-ssd-23.html

I've tested mine with a variety of monitors, both 4K and FHD. The issue is definitelly less severe when using a FHD monitor or a FHD scaling option, however it's still not as cool and quiet as it is when running the same tasks without any external display, even with the lid closed.

BAD MAGIC issue is a cooperation problem related to the T2 chip.

The first line of attack is to do an SMC reset, using the approved procedure. If no joy, Users who have had their mainboards replaced report that the problems was solved.

How to reset the SMC of your Mac - Apple Support

.

Back on page 87, I mentioned my AMD Radeon Pro 5500M was going from 0 to 100% in a spiking fashion with very little in-between. Both my first and my replacement 16" MBP exhibited this behavior, (as well as by many others on this forum.)

After updating to 10.15.4, my activity monitor is now showing 'normal' behavior! That said, I still get temperatures rising quickly and accelerated fan noise when connected to my LG Ultrafine 5k. At least it feels like a bit of progress to normalize the GPU behavior. (I also noticed that the graphics card driver info hasn't changed since the update. Still at EFI Driver Version: 01.01.190.)

(I'm running a zoom video conference and a few idle chrome tabs during this image capture. System running at 68c according to iStats.)

Hi,

I have something that could be similar, but I only experience it when plugging in an external display that is NOT the LG Thunderbolt 5K UltraFine 27" display.

Using iStats Monitor, I see the Radeon High side power usage hit 18W with an external HDMI display, but only 5-6W with the LG screen. I can reproduce this on my LG LP2475W, Dell U3017 and a Denon A/V receiver at 1920x1080.

I would be curious as to what this figure is showing up for everyone else during high/low fan noise situations - the power usage is absolute. Download iStat Menus and report back on this figure!

This seems to be GPU related. I have used a third party ALogic USB-C to HDMI adapter, the genuine Apple one and a DisplayPort to HDMI adapter at the end of a Thunderbolt chain - all seeing the same issue on everything.

Plugging in an external display activates the Discrete AMD Graphics chip, and uses the Discrete graphics for ALL displays (including the built-in) from that point on.

It will stay that way unless you have enabled graphics switching AND you disconnect all External displays AND no high-end graphics programs are running AND no Chrome (which thinks it is a high-end graphics program) .

It's really not normal for it to be at 18-19W just because it's plugged in and taht's why we all suspect that has something to do with the heat and fan issues.

If you force the dGPU on your macbook your energy usage should be pretty low, one other thing you can try is closing your macbook lid while connected to an external display, you *should * see about 4 to 13W GPU usage and no issues. For me I can only have one external display with the lid closed and GPU usage is normal, some people can connect their laptop to two screens and don't have issues as long as the lid is closed.

I have a feeling there is a bug in the driver that makes the GPU go crazy when it's powering more than one display.

Today I was hosting an online meeting with zoom for about 2 hours using an external monitor, the machine was ok, for about an hour (I said ok but it was more on the not ok side), it had some spikes out of the blue were the machine got really hot and the fans were running at 4500 RPM (CPU and GPU usage were almost 0), but other than that the machine was running at 75 degrees and the fans were in the 3000 RPM (I still think that's a lot when CPU and GPU % is almost 0), but after I finished the meeting, zoom started to converting the video to save it on the computer, the machine went full blast (fans at max speed and temperature was crazy too), so I disconnected the external monitor and the fans immediately dropped to 1900 RPM and the temperature to 50/55 degrees, so again I don't think that is a normal behavior, the only difference here was an external monitor connected (with closed lid), and the difference was 5500 RPM against 1900 RPM and 95 degrees against 50 and in both cases CPU and GPU usage % was almost 0.

I would say that this is an issue with AMD's GPUs not being very efficient when using a multi monitor setup with mismatched resolutions.

See this article:

https://www.anandtech.com/show/11278/amd-radeon-rx-580-rx-570-review/2

They say:

..., mismatched monitors would require the RX 480 to go to its full memory clocks even when idling.

They continue with saying:

... Otherwise with mismatched monitors, it always goes to 8Gbps, skipping past 4Gbps and never returning.

If you scroll down, you can see actual power measurements:

RX 480/580 1x LCD 1080p: 76-74W, 2x LCD matched, 1080p: 76-74W, 2x LCD mismatched, 1440p+1080p: 100W

GTX 1060 1x LCD 1080p: 73W, 2x LCD matched, 1080p: 73W, 2x LCD mismatched, 1440p+1080p: 73W



Naturally, with the awkward resolution of the MBP, any external LCD will be mismatched.

I think this can help us get to the bottom of the issue.

Please observe GPU memory clocks. I'm not sure why your current figures are identical, but the average shows 288Mhz mem for the internal screen and 1472Mhz mem for 2 screens connected. Seems to be running at its max frequency.

Please do some further oberservations regarding memory frequency and GPU ASIC power.

Try this:

1. HWinfo has a log functionality (bottom right), before moving to the next step turn it on and save the file somewhere.
2. Test 1: Have your MBP sit idling for about 15 min. Make sure your screen won't go to sleep during that time. Do this from a fresh reboot without any programs open other than HWinfo.
3. Stop the test and safe the file. It will create a text file which you can use to create a graph for GPU memory clock + ASIC power current (!) over time. If you can't do it, I can do it for you.
4. Do the same connected to an external LCD + your internal LCD both running.

Thank you.

What monitor are you using? If I downscale any of these monitors to fullhd (1920x1080) it's 5w, but if it's bigger in any direction it gets to 17w. I don't have 2560x1440 monitor to see if 16:9 aspect would help (as reported by others). Mine is 5500m i9, purchased in europe.

Just tried SwitchResX on macOS - it enables different resolutions for built in display. Tried to toggle internal screen to 1920x1200, with external screen using same resolution via HDMI-TypeC cable (by satechi). Still 20w despite the fact that both monitors are now running same resolution. Even setting both monitors to something lower like 1280x720 results in same 20w. The only way for me to go down to 5w is to use just external monitor using 1920x1080 or any other non-scaled resolution. If I try single external monitor with lets say 1920x1080 but scaled (so that screen content is not screwed but rather letterboxed) - 20w again.

@ntompson

You misunderstand what @Grant has said.

So in your case, you have been connecting via USB-HDMI or Dock. So according to @Grant, that counts as a legacy interface.

The internal display also counts as a legacy interface, so in total you have 2 legacy interfaces which would cause 20W of power consumption.

The way to validate is to connect a single monitor directly using TB3 or DP or USB-C without dock or hdmi in open-lid mode and check the power consumption.

In my case I was able to get the machine working with an external monitor by going to system preferences -> Displays -> Scaled (when you click on Scaled you need to hold the Option key), then I selected the "Show low resolution modes" and I choose 144 Hertz (I didn't change the resolution just the refresh rate, the resolution is 3840 X 1080).

It was on 60 Hertz by default but as soon as I changed it to 144 Hertz the machine got really quiet (fans at 1850 RPM) and now it stays at 40 degrees most of the time and the Radeon is now using 7 watts. I had an issue when I used Quicktime for a screen recording, the machine immediately went crazy, fans full blast and the Radeon was using almost 35 watts (way more than before). So I think this is definitely a driver/software issue, other than than now I can use the machine like I've been using all my previous MacBook Pro.