Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: rmb43 on 2025-05-26, 18:12:06

Title: Strange Render Issue with Threadripper 7970x
Post by: rmb43 on 2025-05-26, 18:12:06

Hey guys,

I have been dealing with a strange issue regarding render speed and rays/total. I render a lot of animations on my render node (specs below) using Deadline, and the issue is that for some reason the rays/total will drop down to almost half of what it is capable of for the same scene and same frame.

With Deadline, I submit the jobs with the "Preview Frames" option, so that it will render 5 frames from the total animation first in order to make sure there are no glaring issues. Then the "Rest of the Frames" is a separate Deadline task that starts rendering after the preview frames are done.  This is how I usually know that I need to check on the renders, because the Preview Frames will render in a certain amount of time (10 min for example) but then the Rest of the Frames will be taking 15 min.

When I observe the frame buffer during this time, it will show a low number like 4,500,000 rays/total. It will continue rendering every frame from then on at ~4,500,000 rays/total.  I have found that If I suspend/cancel the task in Deadline and then restart it, it will fix the issue, and the rays/total jumps up to 9,000,000+. But it doesn't always fix it the first time I suspend the task. Sometimes it will take 3 or 4 tries. And then once it is "fixed", it is absolutely fine for the rest of the frames in that task -- no matter how many frames there are. It won't drop back down to the lower number. 

• It is not scene specific - I have encountered this on several different scenes that are completely unrelated. It also doesn't happen with every animation or Deadline job. It happens almost randomly.
• It's also not frame specific.
• It won't happen in the middle of a Deadline job. How the job starts (normal or handicapped) is how it will render the subsequent frames
• I have tried looking at HWinfo during these times, but I don't notice anything out of the ordinary. HWinfo doesn't report that the CPU is being thermal throttled. Clock speeds when it's "handicapped" and when it is "normal" are almost identical.

The render node: 
BOXX Apexx T3
Threadripper 7970x
64GB ram

I am using 3ds Max 2022 and Corona 11 Hotfix 2.

I am not sure what else to check at this point, so I am posting here to hopefully get some suggestions or theories.

Title: Re: Strange Render Issue with Threadripper 7970x
Post by: maru on 2025-06-18, 16:38:20

Does it only happen when using Deadline? Has it ever happened without Deadline?

The only thing I can recommend for now would be updating to Corona 12 or preferably 13.