Edit 17/11/2020: The long promised refactoring
By doing this mod you will reduce your fan speeds and increase CPU and GPU clockspeeds. By allowing the VRM to sink heat into the bottom plate of the laptop we can alleviate low clockspeeds on CPU and GPU despite having low temperatures in combined loads after 20+ minutes.
This cooling mod non-destructive and can easily be removed before manufacturer service/resale. Yes there will may be some silicon oil left on the components, ymmv depending on thermal pads used.
TL:DR Applying some thermal pads to the VRM components of the MBP
significantly helps reduce fan noise and allows CPU/GPU to run at higher frequencies. This fixes a problem I could not solve with software.
MBP 16 2019 - i9 2.4GHz 64GB 5500M
- ~300MHz GPU, 1.4GHz CPU constant after warming up (Battlefront 2)
- Now 850MHz+ GPU, 2.2GHz+ CPU
- With heatsink and slow fan 900MHz+ GPU, 3.4GHz+ CPU
- Heatsink resting on the bottom casing of the laptop
- Alternatively place heatsink ontop of a laptop cooler then the laptop on the heatsink, make sure contact with the bottom of the laptop underneath the touchbar (or 6 and 7 keys) is good
I work as a Data Scientist, this may not represent what other people define as 'Normal'.
What does this mod solve?
The root cause this solves is high VRM temperatures (Best guess as there are no VRM temperature sensors that I can read). This is a fairly well known issue on similar laptops that I have not seen anyone address on the MBP 16.
What this mod does not solve
- You won't see improved performance for shorter bursts, my CB20 score is basically identical at 3459 vs 3412 (before) within what I consider run to run variance
- The centre back on the bottom of the computer now gets really really hot, too hot to touch so not something you should do something like edit videos on your lap
- I find that I can still comfortably use the laptop on my lap doing normal work. Just not combined loads (Though this was pretty unconfortable even pre-mod)
- The upside of this is that resting this hot surface on a small heatsink with airflow can lead to even more performance
- You will likely see increased CPU and GPU temperatures under combined loads
- My CPU and GPU now reach ~90C when under long combined loads. The VRM being removed as a limiting factor means that thermals/power are now the bottleneck
Final result image: https://imgur.com/szN31ZY
Before shot for comparison (Thanks iFixit): https://d3nevzfk7ii3be.cloudfront.net/igi/yvxkmgnPVDVXNi4A.huge
Thermal pads were cut and applied to the MOSFETS and Inductors of the VRM circuitry. I used thicker pads ontop of the MOSFETS so that I could place thinner pads flat across the Inductors and padded MOSFETS.
- I did not pad the heatpipes coming from the CPU and GPU as I don't have temperature issues with them
- Thanks to wcasdf padding both MOSFETS and Inductors seems to be required for prolonged sessions without throttling
I used a Silverstone M.2 thermal pads I had lying around, the pack came with 1.5mm and 0.5mm pads, both of which I ended up needing. They're rated at 4W/mK which is below the 6W/mK recommended in this XPS 15 mod guide https://www.ultrabookreview.com/14875-fix-throttling-xps-15/
but seem to work fine.
Anectdotes from the comments section
A combination of 1mm and 1.5mm seemed to work best for people
Several commenters have mentioned additional steps, I consider these optional as the base solution resolved all the problems I could see on my machine. Regardless, others have gone further, notably:
- IceStormNG padding the Thunderbolt 3 controllers
- bobba84 for padding additional VRAM VRMs
- bacuulum for removing the black insulating tape on the backplate
Credit Thanks to 1096bimu on the MacRumors forum for the inspiration
XPS 15 mod guide https://www.ultrabookreview.com/14875-fix-throttling-xps-15/
* Exact same problem on XPS 15 models without VRM heatsinks
Related threads I've found https://bootcampdrivers.freeforums.net/thread/792/fix-macbook-pro-vrm-throttling
List of people who have had success with this mod:
There are so many more in the comments that I have not compiled here.