Weird Vram behaviour
Posted: Fri Dec 18, 2020 5:30 pm
Hi there;
While I was testing the new 2020 2 Preview Release I ran into some Vram issues. The scene was working without any problems on 2020 1.5 but throwing insufficient vram errors on 2020 2.
I dediced to optimize my scene and keep an eye on the used vram. After some instancing i got the scene from 7gb down to 4.5gb. This of course significantly improved my render time on 2020 1.5
Then I decided to give 2020-2 another go and started to render again. To my surprise the scene went back to 7gb again.
Wanted to cross check the results so I went back to 2020-1.5 again. When I started rendering the scene went back to 7gb!
Utterly confused I started to render the scene on Live Viewer instead. The used vram went down to 4.5gb. Then when I render the scene in picture viewer it showed the same 4.5gb vram usage.
So it appears that when I render the scene in Live Viewer first the used vram drops significantly. If I render the scene to picture viewer from the start the vram usage skyrockets.
I also noticed that this isn't a case of octane showing wrong vram stats as my render time dropped from 1min25sec to 1min as well.
Is this a known issue? I can get around this thing just by rendering the scene in live viewer first of course but that isn't ideal. Also this wouldn't work with render queues.
Best.
Edit: I have just tried the same trick on 2020-2 and the results are the same. 7gb from directly rendering to picture viewer, 4.5gb if I render in LV first then in PV.
While I was testing the new 2020 2 Preview Release I ran into some Vram issues. The scene was working without any problems on 2020 1.5 but throwing insufficient vram errors on 2020 2.
I dediced to optimize my scene and keep an eye on the used vram. After some instancing i got the scene from 7gb down to 4.5gb. This of course significantly improved my render time on 2020 1.5
Then I decided to give 2020-2 another go and started to render again. To my surprise the scene went back to 7gb again.
Wanted to cross check the results so I went back to 2020-1.5 again. When I started rendering the scene went back to 7gb!
Utterly confused I started to render the scene on Live Viewer instead. The used vram went down to 4.5gb. Then when I render the scene in picture viewer it showed the same 4.5gb vram usage.
So it appears that when I render the scene in Live Viewer first the used vram drops significantly. If I render the scene to picture viewer from the start the vram usage skyrockets.
I also noticed that this isn't a case of octane showing wrong vram stats as my render time dropped from 1min25sec to 1min as well.
Is this a known issue? I can get around this thing just by rendering the scene in live viewer first of course but that isn't ideal. Also this wouldn't work with render queues.
Best.
Edit: I have just tried the same trick on 2020-2 and the results are the same. 7gb from directly rendering to picture viewer, 4.5gb if I render in LV first then in PV.