Rendering speed randomly drops to nearly zero when using RTX

[Alex_M]

I'm experiencing random severe slowdowns when using V-Ray GPU in RTX mode. This has happened on a few completely different interior and exterior scenes now. To sum it up, everything works fine initially and renders pretty fast with the GPU from my signature, but an hour or two later, out of a sudden as if a switch flips, the speed drops to almost zero. If I switch to CUDA when that happens, renderings is fast again. I need to restart Max for my scene to render normally with RTX again. Has anyone else experienced such slowdowns with RTX?

[vladimir_krastev]

Hi, thanks for posting. Have you read this thread? Please have a look and let us know if your issue is similar.

[Alex_M]

Thanks, Vladimir. I took a look, but I don't think it's the same problem. Jiri.Matys reports intermittent slowdowns every few seconds whereas my render speed remains very slow indefinitely until I restart 3ds Max or until I switch to CUDA. I don't get any error messages in the log window when this occurs. I only observe the performance dropping from ~10,000 Kpaths/s to ~500 Kpaths/s. I will try to figure out what triggers this and will write back again if I find out more.

[Jiri.Matys]

Thanks, Vladimir. I took a look, but I don't think it's the same problem. Jiri.Matys reports intermittent slowdowns every few seconds whereas my render speed remains very slow indefinitely until I restart 3ds Max or until I switch to CUDA. I don't get any error messages in the log window when this occurs. I only observe the performance dropping from ~10,000 Kpaths/s to ~500 Kpaths/s. I will try to figure out what triggers this and will write back again if I find out more.

That slowdowns every few seconds was different problem - full VRAM. When I choose compressed textures, it was ok.
But my main problem was slow rendering on GPU. Sometimes it was ok and sometimes it was terribly slow, whole rendering. And I fix that by reinstalling nvidia driver with clean install option enabled.

[vladimir_krastev]

If it is happening in every scene it is more likely to be system related. If it is happening in one scene it is most likely a bug. If you have a few scenes with the issue it is a bit more complex but again you may be using something similar throughout, a plugin or specific workflow for instance.
If you'd like you can send a scene that shows the issue to support.