OCIO Color Management slow

[Delightful_fantasy0D4D]

When I change my OCIO Configuration to ACES 1.2, my after effect timeline can no longer playback in realtime. It will cache, and everything looks normal, buy playback is approx 1/2 to 1.3rd of the speed.
When I turned it back to Adobe Color Managed, it plays fine. (But looks incorrect)

Has anyone experienced this?
GPU - 2 X 4090 RTX FE

[Delightful_fantasy0D4D]

I should note that this is on Windows 11, and the issue persists across AE 2023, and 2024.3

[Shebbe]

1. OCIO in general is more computationally heavy on the system than the icc profile based Adobe Managed.

2. I would recommend using ACES 1.3 as the transforms there are mathematically defined rather than LUT based so don't suffer from lack of precision. The OCIOv2 configs may also be a little bit faster.

[Shane31707926bmjf]

I get this error with 1.3

any idea?

[Shebbe]

On existing effects or a newly added one? Because the 1.3 config uses different names for the color spaces than 1.2 existing OCIO effects in the project may need to be refreshed by clicking reset.

[Delightful_fantasy0D4D]

Computation really shouldn't be the reason its playing back slow, this machine has 128 gb ram, two  4090's RTX, and it's one HD file sequence with no effects.
It plays the same sequence back in realtime with no OCIO color management.

[Shebbe]

While a reduction of 1/2 to 1/3 like you claim in the original post is a lot, you shouldn't confuse raw compute power with phyisical compute speed limitations. There may be diminishing returns. Not using color management at all means no conversion operations are applied anywhere in the compute chain towards the display. With OCIO that is at least one towards the working space and a second to the display.
What's the average time it's taking to render a frame? The performance of native OCIO should be roughly the same as with the opensource plugin from fnord. Is it? Or is that one also much faster?

I would say in general AE's playback and effect compute engine is really slow especially compared to something like Resolve which can chug through 4K exr with colorgrading/effects in realtime. My hope is that some day the whole Mercury engine gets superceeded/improved by one that is at least 2x as fast across the board.