My device:
2019 iMac with 3.6GHz 8-core 9th-generation Intel Core i9 and Radeon Pro 580X
Running D2R on Bootcamp with Windows 10. Have the Windows 10 installed since a year back

Problem:
https://www.youtube.com/watch?v=_fCM8FheNA4
Starting this morning, if I run more than 1 D2R instance, everything starts to freeze up every couple seconds. Check the flame on the Diablo 2 logo on the above video. When running 2 instances, even scrolling on browsers freeze every couple seconds.

What all I have done:
Install latest drivers,
ran the Bootcamp setup to repair the installation,
restarted multiple times,
Reset PRAM/NVRAM
Reset SMC

I have no clue what is broken and I am not able to play.
Note that I have been playing 3 instances since Day 1 of ladder. The problem only started this morning

This post was edited by kingmaker on May 1 2022 03:54pm

This seems like a gpu issue Try running a gpu test

This post was edited by xPailess on May 1 2022 03:58pm

Reset pc

roll back to the 2nd newest update. could be something wrong with the newest driver

the video posted has the task manager. I have 40GB RAM

yeah this is my last option
I wanted to check if there could be anything else before I go for this

check youre temepetures. sounds like overheating download hwiNFO64

40gb?

Try to open task mgr -> details -> d2r.exe -> change priority to "high". Maybe it fixes the freezing

iMac had 4x 4GB RAM in it, I replaced two of them with 16GB RAMs