Laggy display with dual 4K+ monitors MacOS
Ok this is a very easily reproduced bug, but it has a narrow case load where it appears as a problem. If you have dual high-resolution displays--4K, 5K or 6K--and you have the secondary display set to Loupe View and the primary display in the Develop module, the performance on the primary display degrades tremendously. Moving sliders for any of the develop settings is jerky and laggy. It does not happen with the secondary display in other other mode.
It is repeatable on Intel and Apple Silicon machines and happens in all versions of MacOS Ventura and is still present in MacOS Sonoma (latest developer beta). It does not happen on a Windows PC. I have observed it in LR 12.4 and 12.5 but never tried it before those versions so I'm not sure if it existed previosly. It appears to be unique to MacOS and LR.
I am not the only one who has seen this and it can be replicated by other users with the same setup. It happens with even a top of the line GPU in a Mac Pro 2019 and on a top of the line Mac Studio with a 76-core GPU and 128 of RAM.
