Issue with CPU cores affinity resetting.

[Rob Jole]

Hello,

I need to continue to work in another program while rendering test images from scenes in 3d Studio. So for years I have always used windows task manager to set the affinity of the cores that 3d Studio was allowed to use. Usually freeing up 2 cores allowed me to continue with other work. Recently I have noticed that 2018 keeps turning those cores back on. The only difference that has occurred lately was the installation of V-Ray 3.6


Any thoughts on how to keep those cores turned off? Uninstalling the render engine is not an option.

[vlado]

The correct way to do this is to set the priority of the 3ds Max process to "Below normal" (or lower if you wish). Changing the processor affinity has never been the proper solution. You can also set the VRAY_NUM_THREADS environment variable to set the number of threads for V-Ray to use, or alternatively, change the renderers.current.system_numThreads parameter from MaxScript.

Best regards,
Vlado

[particlerealities]

Sorry to revive an old thread, but I've always used the Affinity method to regain multi-tasking abilities. Vlado, where can I find out how to actually run the MaxScript command "renderers.current.system_numThreads" that you posted previously? I was about to get my I.T. guys involved since I don't have admin rights, but it sounds like the MaxScript method is something I should be able to do myself...

[Syclone1]

WOW WOW WOW! I tried the environment variable trick and WOW that has solved a TON of huge issues for me with V-Ray 3.6! Up to using that I had nothing but problems rendering on my main workstation and usually half way through renders all my screens would go black and it would act like the video card or its driver crapped out and I would have to at the vary least restart max as if the computer didn't freeze completely, when the screens would come back then the max viewports were just grey and wouldn't display any of the geometry so I had to cross my fingers and hit save and hope for the best as I restart max and reload my scene. BUT... after finding this VRAY_NUM_THREADS trick its working FANTASTIC!! I set it to 30 of 32 threads and its been rendering just fine all morning with no hiccups or problems! Sorry for running on and on but this is very exciting lol.

I was surprised to see that it didn't just drop 2 threads like I expected with editing the affinity but instead it just takes overall total usage of the CPU to 95%. Im going to test with just dropping a single thread and see if that works.

-dave

[Kirado]

sorry to revive an old thread, I'm having the same issue with vray Next update 2.1

can I set system variable instead of an environment one because I have user on multiple computers?

or is there way of making 3dsmax execute the script on startup as I have another user where we might not have access to setup environment variables.

[vlado]

There are two environment variables that you can look into; one is VRAY_NUM_THREADS which allows you to set the number of threads that V-Ray will use for rendering, and there is also VRAY_USE_THREAD_AFFINITY which, when set to 0 will disable CPU groups support and V-Ray will only use up to 64 cores.

Environment variables can be set per user or globally per system. You can also create a .bat file to set the environment variable(s) and then run 3ds Max.

Best regards,
Vlado

[Kirado]

Hi Vlado, thanks for the fast reply!