Macbook pro GPU temperature Limit On GPU intense tasks like gaming, my laptop starts with increasing the GPU temperature and frequency ( to 85 degrees and max GPU frequency ) then after 5 min or so reduce the temp to 67 degrees Celsius and GPU core frequency and stay there.
This happened both on macOS and Windows Bootcamp.
How to set GPU temperature to the usual standard (80-degree celsius )? 
Every laptop I owned use 80-degree celsius as max GPU temperature.

My Laptop Specs :
15 inch MacBook Pro 2018 
Cpu: Intel 8850H
GPU: AMD Pro 560X

[ It has a T2 Security Chip ]
Problem solved on Bootcamp with GPU Driver's provided by AMD.

https://www.amd.com/en/support/kb/release-notes/apple-boot-camp
Make sure to remove Apple stock GPU Driver with "Display Driver Uninstaller" on Safe mode.
Do not use the "Apple" or "bootcampdrivers.com" drivers.
You must install Radeon pro driver ( It has blue system tray icon )