Performance issues with rendering time at large sizes

[diego6S3FN]

Hello, for some time now I have been noticing a performance issues with the rendering time of large frame sizes in Arnold.

 

For example in the attached VR render in Over / Under format the animation is very subtle, just a movement in the water and the soft wind in the branches of the vegetation and clouds:

In 512 x 512 px renders I have had render times between 1:34 and 1:48 minutes which I find an understandable variation but in the 4096 x 4096 px renders I have had time variations between 21:30 to 41:50 minutes this is really a problem when planning a production.

The document is exactly the same with no variation other than the render size.

The computer is a 32 cores Rizen rendering with 64 thread cpu with 64 GB Ram. on WIndows 10 Pro.

I have observed this problem also with GPU RTX 3090 that renders very fast in small sizes and slower times than CPU or infinite times in sizes like 6144 x 6144 pixels.

This is not a problem related to this scene, I have seen this behavior in other scenes with a lot of geometry. It would be nice to know how to avoid this irregular behavior at large render sizes.

Thanks in advance,

Diego

[Stephen.Blair]

Hi

First thing I would do is compare logs for different renders. Where is the extra time being spent?

Higher resolution is going to take more resources.

[diego6S3FN]

Hi Stephen thank you for your suggestion, I guess the verbosity level "Info" will be enough for this, I will activate it in the next render to see the differences and I will share it.
It would be nice to read some information to know how to interpret the "Logs" of the console. I think I don't use it much because I don't understand it and I don't know what to do with the information it gives.
The padding displacement warnings for example always gives me many with small differences in what Arnold advises but in these scenes it takes a long time to adjust all these measures and many times it still shows Warnings even if you adjust the Padding averages.

It would be great a tutorial showing how to interpret the console logs.