Denoiser slows down calculation (doubled render time)

[Micha3D]

Hi,

I tested a v3 scene at v4 (Rhino plugin) and a frame of my animation needs 24s instead 11s before, if I enable the denoiser. The sampling rate of MSamples/s is nearly halfen during the calculation. What do you think? Is it caused by the GPU setup?

-Micha

[Goldorak]

Make sure it is set to “denoise in completion” or else it will denoise whole rendering, slowing both down (in expansive for giving you live denoising updates in the viewport)

[Micha3D]

I enabled "denoise on completion" and it's the same. Also if I disable denoise at the device setup, than the render time is more than doubled, also if no denoising is done in this case.

[Goldorak]

I enabled "denoise on completion" and it's the same. Also if I disable denoise at the device setup, than the render time is more than doubled, also if no denoising is done in this case.

Can you try just rendering+denoising vs. Rendering on just the 1080 Ti and see if the speed is also half?

[Micha3D]

Only 1080ti enabled - denoising on 37s and denoising off 20s. Also I don't understand why enabling the old 780 halfen my render times - (denoising off) 1080ti 20s and 1080ti+780 9s.

[Goldorak]

Strange. Can you export to standalone and see if this is still the case? What if you increase the max samples by 10? What is the resolution?

[Jolbertoquini]

Hi

I have same results on deadline when I submit a render 10 frames per task gets 1 min if I just activate denoise the render take 2 min. My setting is at completion.

Funny thing via batch render script the denoise is faster I can see that.
I will investigate this more deep soon we are less in trouble with deadlines. Due plugs.

Cheers
JO

[Micha3D]

Strange. Can you export to standalone and see if this is still the case? What if you increase the max samples by 10? What is the resolution?

It's the same at the standalone. Resolution is 1080x1920. Which samples should I try to increased? I increased the kernel samples from 800 to 810 and it's the same. I will send you the ORBX file for testing.

[J.C]

We internally enable around 20 render passes (diffuse, reflection, etc) for denoiser input. The slowness is happening because of the huge additional memory that needs to be transferred between the host and device. We are working on a new denoiser model that will work with very few render passes to solve similar issues.

[Micha3D]

I hoped the slow down is critical for quick rendered scenes only, but I tested an interior and the render time jumps from 4min37s to 9min33s for the same sample count (1000). So, I'm very curious for an improvement of the denoiser.