P: Slow UI when using Mac and Custom Display Profile

Having the same problem ... making it almost unusable.

You said it, man. 

unacceptable. 

Perhaps unacceptable but choosing the default sRGB profile seems to solve the problem.

I'll echo that my older Mac setup is suffering from the v10.0 update.  I tried running with base color profiles recommended to no effect. Library browsing seems to be the only function affected - persistent spinners on scroll refreshes/hovers. I've disabled most overlay functions however remained completely unusable. I've reverted to v9.4 and am back up and running. But paying via subscription model i'd prefer to be running best/latest!  

Machine specs:
Mac Pro (Mid 2010) with lots of internal hardware upgrades

Processor: 2 x 3.06 6-Core Intel Xeon

Memory: 64 GB

Disk (Primary): SAMSUNG MZHPV256HDGL (M.2 Interface: PCIe 3.0 x4 lanes)

Graphics: Radeon RX 580 8GB

Monitor: LG 27UK850-W 27" (3840x216)

P.S. I should note that i run the Lightroom CC (non-classic), latest version, and it flies!

I see the same thing happening here.

I found the cause of the problem on my MacPro with individual calibrated profile from EIZO Color Navigator:

If you move the image in the library module permanently, only the CPU is calculating, not the graphics card. If you move the image in the Development-Module and in Photoshop permanently, the graphic adapter is calculating and the moving is flawless. So the calculations made in the Library-Module for the preview and the loop does not involve the graphic adapter on my system (Catalina).

When scrolling through the Loop or slide around the preview in Library module with profile AppleRGB it is much faster but also there no graphic adapter is involved. 

Conclusion: Involving the Graphic Adapter in the calculations for display in the Library adapter would increase the speed and "snappiness" dramatically. 

So Adobe. This is what you have to do to solve this problem...

Try this. Save as your custom display profile with a new name (change internal name to match) from ColorSync and see if that makes any difference.

Then why do you engage here, billwithlotsofnumbers?

But is there a compelling reason to use LR10 as opposed to using 9.4 that does not have this problem allowing you to use your normal workflow for the display/profile?

Well that's a good question each user has to decide on and hopefully they have backed up their older catalogs. 

But is there a compelling reason to use LR10 as opposed to using 9.4 that does not have this problem allowing you to use your normal workflow for the display/profile?

For me LR 10 sRGB is still slower then 9.4 display/profile.