ID 514390 - OCIO soft effects reduce playback speed compared to older Nuke Studio/Hiero versions

Problem summary
OCIO soft effects reduce playback speed compared to older Nuke Studio/Hiero versions
 
Customer reported version
hiero.13.2v2
 
Customer reported platform
windows10
 
Steps to reproduce
 
1) Open Nuke Studio/Hiero
 
2) In Project>Edit Settings>Color Management, set the OpenColorIO Config to an ACES config, like aces_1.1

2) Import a 4K EXR sequence from a fast local drive. For testing I used this footage copied from the network to a local drive: /netshare/support/4Pete/footage/4KEXR/4KEXR_#####.exr)

3) Add the footage to new sequence, and set the Output resolution to 2840x2160 UHD_4K and the Frame Rate to 60
 
4) Once the clip has cached, playback the Viewer, it plays at 60fps
 
5) Add an OCIO soft effect, like OCIOCDLTransform
 
6) In the OCIOCDLTransform properties,set the working space to Output - Rec.709
 
7) Playback the cached Viewer, it now plays back much slower, around 30-40 fps
 
*Happens with other OCIO soft effects and other color spaces, but Output - Rec.709 seems to be particularly slow. The more OCIO soft effects you add, the slower playback becomes.
 
Expected behaviour
For the cached frames to playback at the same fps:

 
Actual behaviour
The Playback speed is significantly worse, often half of what it should be.

 
Workaround
None
 
Reproduced by support
This bug has been reproduced in:
Nuke Studio 13.2v2 - Windows 10, CentOS 7
Nuke Studio 13.1v1 - Windows 10, CentOS 7 - regression
 
Unable to reproduce bug in:
Nuke Studio 13.2v2 - macOS Monterrey * Performance did not seem to drop, though after adding enough OCIOCDLTransform soft effects, the viewer would just render black. Testing on 2022 MacStudio, M1 Ultra.
Nuke Studio 13.0v9 - Windows 10, CentOS 7
 
*Performance difference varies between hardware, so may need more soft effects to see the issue.
 
Earliest version tested
Nuke Studio 13.0v9 - This issue doesn't appear in this version and has regressed