Denoiser Hardware requirements

hallo_ich_bins1815_74a34261fc

Hello,

 

after Iray Renders (on GPU only!) sometimes the denoiser kicks in and sometimes it doesn't. There is no error, if it doesn't kick in. he Logfile does not provide any hint either. So I am wondering what the hardware requirements for the denoiser are.

1. If a scene renders in Iray on my GPU (960 4Gb), should the denoiser allways kick in?
2. If not, what are the requirements? I know my PC (i5 3750K, 960 4Gb, 8GB Ram) became a potato over the years and I plan to replace it when the 7nm Cards will launch, but right now I have to stick with what I have. If it is the Ram, I could get a cheap upgrade to 16GB Ram, but a new Graphics card, that is much faster is sadly not an option right now.

Edit: This is from a scene where the denoiser did not kick in:

Rendering in NVIDIA Iray

Compiling Shaders - 0/1

Rendering image

Rendering...

Iray VERBOSE - module:category(IRAY:RENDER): 1.4 IRAY rend progr: CUDA device 0 (GeForce GTX 960): Processing scene...

Iray VERBOSE - module:category(IRAY:RENDER): 1.3 IRAY rend stat : Geometry memory consumption: 155.868 MiB (device 0), 0 B (host)

Iray VERBOSE - module:category(IRAY:RENDER): 1.3 IRAY rend stat : Texture memory consumption: 1.34376 GiB for 76 bitmaps (device 0)

Iray VERBOSE - module:category(IRAY:RENDER): 1.3 IRAY rend stat : Lights memory consumption: 948 B (device 0)

Iray VERBOSE - module:category(IRAY:RENDER): 1.3 IRAY rend stat : Material measurement memory consumption: 0 B (GPU)

Iray VERBOSE - module:category(IRAY:RENDER): 1.3 IRAY rend stat : PTX code (60.5 KiB) for sm52 generated in 0.188s

Iray VERBOSE - module:category(IRAY:RENDER): 1.3 IRAY rend stat : Materials memory consumption: 315.898 KiB (GPU)

Iray Iteration: 1

Richard Haseltine

The denoiser does require GPU resources, so if the render drops to CPU the denoiser should not be used; if the render uses the GPU it's possible that the denoiser will still lack sufficient resources, I'm not sure if it would fail in isolation or cause the whole render to drop to CPU. I don't believe it is expected behaviour for the denoiser to run on a CPU-only render.

hallo_ich_bins1815_74a34261fc

The CPU part is not an issue. The GPU rendered the complete scene and after that - nothing.

I forgot to mention that I set the start iteration of the denoiser as the max Iteration of the render, so that the denoiser begins its work after the render is "finished". If I lower the resolution or delete a figure depending on the scene, then the denoiser works fine. So I really think that my hardware is strong enough to render some scenes with Iray on GPU, but to weak for the denoiser. That sounds a bit wiered, but I just would like to know where I can check that or if anyone of you have a similar experience.

kenshaw011267

I think you are simply running out of VRAM when the scene pushes up against the VRAM max on the card before the denoiser runs.

hallo_ich_bins1815_74a34261fc

Yeah, I thought of the same thing. That's the reason why I set the "start denoiser" = "max iteration". So I hoped the denoiser starts after the last render. But to verify the lack of VRAM, I need to know the hardware requirements of the denoiser, as in the thread starting post mentioned.

kenshaw011267

No one knows but the only times I've had what you're decribing happen is when my VRAM was nearly maxed.

goods1nn3r

Sorry for necro, just wanted to share some of my observations about denoiser and VRAM.

I have 6 GB VRAM nvidia 1060. I'm using GPU-Z to monitor VRAM usage, so if that is not giving correct values then my judgement can be wrong.

I don't have preceise value of VRAM used by post denoiser, but it seems like everytime my VRAM is filled with less than 5GB while image is rendered (but before denoiser should start), denoiser will work, and indeed it is taking some more VRAM. Even if VRAM usage is like 5050 MB, denoiser is not working. So my advice is to limit the scene to 1GB less than Your VRAM size.

On the side note, it's a bit weird, since the most space I've seen denoiser was using (or precisely - VRAM usage increase after denoiser started) is about 250 MB, so full 1GB seems to be not needed, but that is how it's working.

Cheers All

 

ps. tested on 4.14