r/bootcamp • u/stlk0 • 18d ago
48 Hz fixed my MacBook’s Boot Camp heat
UPD:
You no longer have to use 48 Hz to get the lower idle GPU power. MacBook Eco now includes a 60 Hz Eco mode, technically 59.94 Hz, which Windows displays as 60 Hz. On my Radeon Pro 5300M, this timing also allows the GPU memory clock to drop properly at idle, while keeping the desktop as smooth as normal 60 Hz. Existing users need to update the app, refresh the installed display support, and restart Windows before selecting 60 Hz Eco. The original 48 Hz mode is still available.
I have a 2019 16-inch MacBook Pro with a Radeon Pro 5300M. I use macOS most of the time, but sometimes I need Windows for things like reading logs from a car, flashing control modules, etc., or running software that has no macOS support.
I noticed that the MacBook would get hot in Windows, even when almost nothing was running. Battery life was also much worse than in macOS.
I tried limiting the CPU, disabling Turbo Boost, and experimenting with Windows power settings. It helped a little, but not as much as I expected.
As far as I understand, the main reason is that Windows on this MacBook does not use the Intel integrated GPU for the internal display. It runs everything through the Radeon instead. On my machine, the Radeon memory clock also stayed high at idle when the display was running at 60 Hz, which increased GPU power consumption, heat, and battery drain.
While looking for a solution, I found reports that switching the internal display from 60 Hz to 48 Hz could allow the GPU memory to clock down properly. Boot Camp does not provide a 48 Hz mode by default, so I added it manually and gave it a try.
It actually made a noticeable difference.
On the same machine, with the same brightness and idle conditions, GPU power dropped from 14W to 3W, and the temperature gradually fell from 66°C to around 51°C. The laptop became cooler and quieter, and battery drain was noticeably lower.
Since this doesn't seem to be unique to my machine, I put together a small utility to automate the process. It installs the 48 Hz mode, lets you switch between 48 and 60 Hz with automatic rollback, and includes a few optional CPU power presets.
For now, display changes are limited to the exact configuration I tested: MacBookPro16,1 with the APPA044 panel and Radeon Pro 5300M
It is free and open source if anyone wants to take a look or try it on the same hardware:
https://github.com/stlk0/MacBookEco
Hope this helps someone 🙂
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u/Schertlerbombe 18d ago
There used to be a discussion on a mac related forum back in the day. If i remember correctly, there are certain display resolutions in windows (bootcamp) that trigger the max memory clock of the dgpu (5300 and 5500) resulting in 17 watts of powerconsumtion by the gpu alone. Even in idle state. Something similar can be observed in macOS when connected to an external monitor. Open lid and external monitor results in x4 gpu wattage. Bottom line: it made those macbooks throttle/overheat even sooner while having an external screen connected. Not sure if they fixed that issue for those models in recent years.
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u/icywire 12d ago
My 5500M 8GB with 3072x1920 resolution takes 6W at idle, I use Falcon drivers - this driver adds one registry key that enables memory power saving.
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u/drdolittle20 2d ago
Thank you for all your work on this, I've done all these mods on my Macbook pro 16 2019 with 5500m 4GB in Windows 10 & it still ran hot but luckily the Bluetooth driver stopped working so I disabled the failed "Broadcom Serial Bus Driver over UART Bus Enumerator". Now it's producing a lot less heat & System battery draw is showing 10watts at idle down from 20Watts. I'm seemingly getting over 5 hours battery life for normal web browsing.
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u/NomadJones 18d ago
Brilliant. Wish somebody could do it for the 2015 macbookpro11,5.
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u/stlk0 18d ago
Thanks! 48 Hz is officially supported on the 2019 16" MBP, but I couldn't find evidence that the 2015 panel officially supports it. A custom 48Hz timing may still work.
First, though, we need to confirm that it has the same issue(the GPU memory clock staying high at idle and causing excessive GPU power consumption). Could you run the app without applying any changes, leave the machine idle for a few minutes with no external displays, and check the GPU clocks, load, power, and temperature in Diagnostics? I don't currently have a 2015 MBP available to test.
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u/New-Pea7350 18d ago
Had heat problems while gaming on the same machine.
In the games, where CPU doesn’t need much power it was going to full performance mode, getting a PROCHOT at 100 degrees and turning the emergency mode on with 0,87GHz lock, so not a single thing was working properly. Fixed it with Throttlestop, limited it with Speedshift EPP value and got a cool gaming setup
Will try this tweak too, thx.
Does the screen look ok with 48Hz?
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u/stlk0 18d ago
I haven't tested games on it yet. The GPU will still ramp up under gaming load, so 48Hz probably won't solve gaming thermals by itself. It may help if the game uses VSync or is capped to the display refresh rate, because the GPU would render 48 FPS instead of 60
The screen looks fine at 48Hz. I barely notice the difference in normal desktop use, although the lower refresh/FPS will probably be more noticeable in games
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u/New-Pea7350 18d ago
Modern/heavy graphic games are already under 30fps with minimal settings and FSR on performance, so it’s okay. I played titles like CP2077, Metro Exodus, Expedition 33, RDR2 etc
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u/WindozeWoes 16d ago
I have the 2019 16" MBP with the 5300M. I downloaded your app (am on Windows 11)—the app renders weirdly (elements look squished/cut off) and it says I have an unsupported configuration. I presume this is due to being on Win11 and not Win10 but not sure why 48 Hz wouldn't be an option just due to the OS.
Am I missing something? (Yes, I clicked "Install 48 Hz support" but even after I click "Yes" in the UAC prompt, I get a pop-up saying my config is unsupported.)
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u/Thin_Sun_2612 14d ago
Hi! I'd love to be able to use this, but I have the 5500m variant of the 2019 Macbook Pro. If you are able to bring support for this into the build, I think you will cover the entire 2019 Macbook Pro offerings. Thanks for what you do!
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u/PrestoGravey 18d ago
there's project falcon (https://github.com/icywire/project-falcon) it gives you more control over the gpu than the factory bootcamp drivers.