Better to allocate one or all GPU's to Denoising Process?

[GIOLETS]

I'm in a multiple GPU configuration and I've noticed that if I allocate only one GPU to the Denoising Process (that till today I thought the best Otoy suggested choice), the other GPU's often goes to 0% of usage when rendering.

If I instead assign all the GPU's to Denoising all of them run all the rendering time at 100%, lowering in a considerable way my render time.

So I ask what is the Otoy suggestions on this aspect: is better to enable all the GPU's for Denoising or not?

Thanks to all.

Luca

[bepeg4d]

Hi Luca,
you have not set the Priority, that should be set to LOW, and enabled for the GPU connected to monitor.
Please, share a screenshot like this one:


ciao Beppe

[GIOLETS]

Hi Beppe!!! (Just a personal note: I'm very happy to hear from you)

Here my GPU connections and the (corrected) Octane Device Setup.

[bepeg4d]

Ciao Luca
ok, adesso è più chiaro, la priority non ti serve perché usi una 780 per i monitor, non abilitata al rendering.
Quindi immagino tu stia usando i driver Game Ready invece che Studio, dato che la 780 ne blocca l’installazione.
I bus PCI hanno tutti la stessa velocità?
Cosa succede se abiliti il denoise solo sulla seconda 2080?

Damn, I have written in italian...

ok, now it's more clear, you don't need the priority because you use a 780 for monitors, not enabled for rendering.
So I guess you're using Game Ready drivers instead of Studio, as the 780 blocks their installation.
Do all PCI buses have the same speed?
What happens if you enable denoise only on the second 2080?

ciao Beppe

[GIOLETS]

Hi Beppe, here my test enabling only the second GPU.

I have noticed that this time is the first GPU that goes to 0%, but more often and for a smaller period (about 3 seconds).

I give you other pieces of information, for your better investigations:

1) I use the Game Driver 446.14 for the reason you mentioned (my 780 isn't recognized with Studio Driver), but I am able to load also the Studio Driver forcing the System to set a GTX 1050 instead of RTX780. So, if you consider it useful, I can make the same test loading Studio Driver.

2)Another thing that could be important: I have to use NVIDIA MSI mode utility (https://nvidia.custhelp.com/app/answers ... tchdog%20v) in order to fix the "watchdog violation error " that I had on my Windows 10 system with a PLX Motherboard. I don't know if in some way this influences the GPU behavior.

[bepeg4d]

Hi Luca,
just to be sure, AI Denoiser has the On completion option enabled, correct?

I have not access to a system with more than 2x GPUs at the moment, anyway I have tried to reproduce your issue without success, both GPU are always working at 100%
But I’m working with Nvidia studio 451.77, under Win 10 2004.

ciao Beppe

[GIOLETS]

Very good investigation Beppe, I've unchecked "Denoise on Completion" because sometimes my rendering stopped at the end without saving the image (but with an old 2019 version), so I have left unchecked this feature for better reliability.

Now with the switch checked the GPU works the same at full speed.

So the best setup for us should be:

1) only one GPU used for Denoising
2) Leave "Denoise on completion" checked

Correct?

Thanks for all.

Luca

[bepeg4d]

Hi Luca,
yes correct!

Please note that if On completion option is disabled, the rendering time is longer, because the denoiser is applied at every interval, so always better to keep the option enabled.
It is useful to disable it only when you are defining for the correct max sample value before applying denoiser.

Happy GPU rendering,
ciao Beppe