What is the supported GPU for the intel denoiser to run on? It seems its not Nvidia (CUDA).

OIDN should support Metal and CUDA GPU devices. Some combinations of driver/GPU do not work with the CUDA device. You can check if it works on your config by running idenoise -V 1 Mandril.pic denoise.picin a Houdini shell.
If your config is not supported, you should see: OIDN: GPU device error - fall back to CPU: unsupported device type: CUDAWe hope to support more devices in the future.

yeah, I am getting that (also in the log viewer while rendering in the viewport). I am just a little surprised that an RTX A4500 with the latest drivers is not among the supported combinations. are just the ada cards supported?

mark
You can check if it works on your config by running idenoise -V 1 Mandril.pic denoise.picin a Houdini shell.
If your config is not supported, you should see: OIDN: GPU device error - fall back to CPU: unsupported device type: CUDAWe hope to support more devices in the future.

I get the same error with a 3090 and current drivers on Windows.

https://www.openimagedenoise.org/ [www.openimagedenoise.org] says Turing and later is supported and min driver version is 452.39 on Windows. I'm using 555.99

Same error here on a 3060 with 556.12