Vray Next Update 1 Freezing if using all threads

[ice_creative]

I wanted to flag an issue with rendering freezing on Vray Next Update 1 with all settings at default on bucket rendering (directly related to thread usage).

Been a regular user of 3.6 up until recently where I moved to 3ds Max 2019 and tried out the Vray Next Update 1. I soon noticed that renders would freeze midway through, I always render with the VFB and the whole PC would lock/freeze so I had to manually restart it with the power button on the case. I was unable to pinpoint a direct cause for a while and worried my Ryzen 1800x CPU was overheating or misbehaving.

However, I found similar forum threads of windows 10 users with different CPUs having the same issue with Vray Next. As I am running on the trial, I will swiftly be moving back to 3.6 for the sake of my own sanity mid-projects. Related forum post attached below.

I was able to prevent the freeze by changing the
VRAY_NUM_THREADS environment variable to 1 less than the total thread count of my CPU (so 15 I think). Since then, performance has been fine. I do not run any other programs while rendering either and I'm not the first person to face this issue so I hope that it can be fixed in a future update hopefully before I update to Vray Next for good.

[yavor.rubenov]

Hello,

There are some lengthy discussions about that issue in this topic:
https://forums.chaosgroup.com/forum/...-3-6-vfb-hangs
and some other possible solutions here:
https://forums.chaosgroup.com/forum/...884#post975884

Generally - the problem is with the Windows task scheduler and there is not much we can fix. The render itself is not frozen - Windows is not properly updating anything while the render is running.

Best regards,
Yavor

[ice_creative]

Hello,

There are some lengthy discussions about that issue in this topic:
https://forums.chaosgroup.com/forum/...-3-6-vfb-hangs
and some other possible solutions here:
https://forums.chaosgroup.com/forum/...884#post975884

Generally - the problem is with the Windows task scheduler and there is not much we can fix. The render itself is not frozen - Windows is not properly updating anything while the render is running.

Best regards,
Yavor

Thanks for responding during the festive period, I understand if it's an OS issue (albeit a crappy one). Are there any suggested workarounds?

One render froze with approximately 10mins left so I waited a further 10 mins but got impatient - I will try some more renders in a few hours and keep an eye out for the next freeze to confirm it is definitely the task scheduler not updating as the whole machine freezes.

I needed to get some renders done today sharpish so I was unable to investigate further but I have reset the max threads variable and removed it from environment variables so the CPU usage is back to 99% during renders. I also set windows power settings to 'Performance' instead of 'Balanced' and have not had another freeze for the past few hours.

The reason I want to check is because the moment the freeze happens, my Corsair h100i watercooler fans calm down a lot, also the HDD write light on the front of my case stops blinking which leads me to think it has stopped doing anything?

[ice_creative]

Disabled Control Flow Guard for 3ds Max 2019 and for the past 5 renders that froze before haven't had a single freeze. Hopefully this thread is of help to anyone else who faces this issue! I will report back if I have any more findings, thanks for your help!