128 threads in AMD RYZEN 3990x-64 + Corona 6.1 = Slow rendering ?

[lowrider]

Hello, i have big problem witch my new computer in 3ds max 2021 . Windows 10 pro, AMD RYZEN 3990x-64 - in Corona benchmark and Cinebench benchmark everything is ok, i have full 128 speed threads, but in the 3dsmax scene and Corona 6.1 i have very slow rendering...In 3ds max 2021 and Corona 6.1, CPU threads work only on 64 threads, and 64 are completely unused. The situation is so strange that it only happens in the 3dsmax and Corona environment inside the scene. In a separate Corona, Vray, and other benchmark, the computer runs all 128 threads. In addition, I noticed that I do not have access in the task manager to set the processor affinity, it displays "no access" which is strange because I have never had such a situation. I would not notice this fact if I did not compare the rendering speed of the old computer with the new one, where 64 threads are faster in renderings than 128 threads. :(

[danio1011]

Just as a test, have you tried running 3ds Max as Administrator and seeing if that helps?  Almost sounds like you are having a user permissions issue that, for some reason, affects 3ds max.  Just a diagnostic thought\test.

[Juraj]

Windows doesn't let you set affinity for processes that span multiple CPU groups, this limitation was always there.
You can use tool called ProcessLasso to do it though. I experiment with various settings for my 3990X but they didn't yield improvement for my issue (I find 3dsMax to be slow when IR is running, regardless of how many threads are left to be empty).

I am Corona 6, no issue with 3990X, will install hotfix early next week and re-check.

(I just remembered, few months ago I installed daily build and suddenly my 3990X also run only at 50perc. utilization. After reverting to release 5.0 build, the issue vanished instantly as well)