Optimizing GPU render settings

[eraclito_perseus]

I'm going through the official resources here https://help.autodesk.com/view/ARNOL/ENU/?guid=arnold_for_cinema_4d_ci_Tutorials_html

to see if there's something specific about optimizing render times when using the GPU.

So far, I wasn't able to find much. 

My knowledge in this regard is limited, knowing only that when switching to GPU, the few settings available are AA max samples (which I usually keep around 4), the adaptive threshold (usually left on default, 0.015), and the filter, which I also leave on default (gaussian=2).

Is there some resource online where I can learn if and how to squeeze the most out of Arnold GPU rendering options?

I'm currently on a machine with two 3080ti, and I might need to render a UHD project, about 15-10 seconds. The geometry is of medium-low complexity, as the materials, but there's some FOG volumetric (which, in Arnold, it looks quite nice by the way).

Any learning material that could put me in the right direction would be appreciated.

P.S. I'm also leaving Intel OIDN denoiser on.

[eraclito_perseus]

For instance, one thing now caught my attention, which is the clamping option.

https://help.autodesk.com/view/ARNOL/ENU/?guid=arnold_user_guide_ac_render_settings_ac_clamping_html

If this works as in Cycles, it might reduce the render times. Of course, one has to be aware of the possible downside of tweaking such an option, which, from my understanding, may lead to clipped values in the brighter areas.

[lee_griggs]

What exactly are you trying to optimize in the scene? It all depends on what you are rendering. Every scene is different. Can you share some details/images/renders about your scene? Complex shaders? Displacement? Thousands of lights? Heavy geo?

Depending on what you are rendering you may need more Camera (AA) samples when rendering with GPU.

I tend to use OIDN during IPR and then when I am ready for a final render, I will fine tune Camera (AA), etc without it and then turn it on for final rendering to clean up any remaining noise.

I would go over the Removing Noise tutorials: https://help.autodesk.com/view/ARNOL/ENU/?guid=arnold_for_cinema_4d_ci_Tutorials_ci_Removing_Noise_h...

Sampling: https://help.autodesk.com/view/ARNOL/ENU/?guid=arnold_user_guide_ac_render_settings_ac_sampling_html