P: Slow UI when using Mac and Custom Display Profile

Then it's likely that this is triggered by specific GPU calls executed by LR on your particular hardware. FWIW, I've seen a variety of display-related issues on 2013 Mac Pros that I haven't seen on any other system. Some of them can be resolved by using a different Thunderbolt port or switching to an HDMI display connection. Perhaps that's worth checking out...

Edit: the issues I mentioned don't concern artefacts. They relate to displays not waking up after sleep, display arrangement changing after sleep or reboot, etc. It seems to me that there is something 'odd' about the GPU-implementation on the 2013 Mac Pros, but I've never delved deeper into the subject.

*Ron_Pfister Thanks Ron. I never see this under any other circumstances and I don't see temperature spikes. The Mac Pro (2013 "trash can") responds to GPU spikes as expected. For example, the fan speeds up when exporting 300 photos from Lightroom and slows down to almost in audible level right after it's done.

(others in the LR preview program have reported similar green blocks behaviour)

The only way to be certain is to swap GPUs if that's possible on your hardware. In my experience, such issues are triggered on faulty GPUs either by high GPU load or rising system/GPU temperature. In the latter case, the issues only appear once the system has been running for a while, irrespective of GPU load. It might be worth running different GPU benchmark apps to see if you can trigger any issues. Do you ever see temporary artefacts on your display (green or magenta blocking on parts of the screen)?

Thank you *Ron_Pfister 

How can I investigate this? Is there a diagnostic that can be done? It doesn't manifest in any other version of Lightroom, nor on any other app (Photoshop, Capture One, some OpenGL accelerated apps, etc.)

Adam, the behaviour you describe of your workstation reminds me of issues I've seen on systems with faulty GPUs (display artefacts, hard lock-ups and spontaneous reboots without any updates of the UI). This might be something worth investigating...

I just updated to 10.1 and there has been no discernible change for me at all: still the same sluggish performance in the library module when using custom display profiles (and no issues with local adjustments - with or without GPU support enabled). I'm back to using the sRGB profile on my secondary display...

@Adam Crowe Bummer. No problems with Canon CRAW from a R6. I've got graduated, radial and brush on an image and it's working fine.

- Custom monitor profile

- GPU on

*SydLow GPU on.

I have just downgraded back to 10.0. The Library module is discouragingly slow but at least the Develop module works well.

Is this with GPU on or off? Or it doesn't matter?

*SydLow Unfortunately, it's just done it again over here. That's why it's taken me so long to reply. The smallest adjustment makes the whole OS irresponsive.

And also, this happens: