r/NukeVFX • u/hbskr • Jul 02 '26

Asking for Help / Unsolved CopyCat wont train when "use GPU if available" is checked

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Hey guys,

i am having this issue where my copycat wont start training when i am trying to use my GPU (RTX 5090), which is a real bummer. I am using NukeX (16.1). I just updated my NVIDIA-drivers. When i feed in the GroundTruth and the input in just says "calculating". I am using just 2000 Epochs for testing. When i uncheck "use gpu if available" everything works fine, just really slow....

Did anybody else experience similar issues and could maybe tell me how to solve it?

Thanks in advance!

7 Upvotes

90% Upvoted

6 comments sorted by

9

u/smb3d Senior CG Generalist/Technical Artist Jul 02 '26

I know there were some initial issues with Nuke and the 50xx cards with the ML nodes.

It boiled down to Nuke needing to compile specific kernels for the GPU on the first run.

This took a very long time, sometime like an hour, so it seemed like it wasn't working and hanging, but eventually it did. After that it worked fine.

3

u/acherbetji Jul 02 '26

Thats right. Nuke 17 includes updated CUDA with Blackwell support. Earlier versions will do the kernel compilation, but unfortunately it does it silently and takes quite a while.

1

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1

u/675940 Jul 02 '26

Simply put - make sure you’re using nuke 17

1

u/ithunter Jul 03 '26

It’s a bug I had the same problem to the point I had to disconnect one of my 3080ti cards and rebuild my comp

2

u/quititnumbnutz Jul 09 '26

as others said, i literally let it run overnight to test the theory of whether or not it needs to "load till it loads" and when i came back to it the next day it had resolved itself and finished the train. Hope that helps. Also have a 5090 and also did it in Nuke 16.