P: Slow UI when using Mac and Custom Display Profile

Same. Mac Pro 5,1, Mojave, 2x 6-core 3.46GHz, 96GB RAM, Radeon 580RX, Samsung EVO SSD driven on an ACHI controller.
Three screens, the main 4K display running at 3840x2160 and two 1920x1080.
No matter the setting LR 10 is CRAWLING.

One would think it's a decent computer and Lightroom 10 brings it to its knees – no, it makes the machine unusable... Every move in LR takes eons to complete.

Activity monitor shows hardly any processor use & any setting regarding GPU performance or resolution makes no difference. Photoshop performance is a-OK, but it's not my main tool anymore. I'm seriously considering a.) switching to Windows b.) Ditching Adobe altogether (unfortunately we don't have many options in our industry.)

The same software runs OK on another 5,1 with High Sierra and lesser RAM, processing and graphics power and on a little MacBook Air & Mojave with an HD monitor. Go figure. 

Edit: the other machine maxed out on 9.4 w/ High Sierra and I'll try to downgrade on my main machine. Not happy.

same here, went back to 9.4 and did the move to 10.1 today, just to realise, no change. STILL SUPER SLOW... it unusable (and even 9.4 is too slow - by the way)

MacPro 5.1

AMD Radeon 580RX

46 GB RAM

System on 1TB NVME2 SSD

seriously ADOBE, what are you guys doing with LR ???

why is this not being fixed ? first 10 and then 10.1 ??? and still the same ???

At least some info on your progress would be appreciated...

@Rikk First of all, thanks for steering me in the right direction.  I dropped from LR10.1 to 10.0 and the problems went away.  Here's some additional details that I learned through repeated attempts to diagnose that might help the coders at Adobe to straighten this out. 1.)  The problem on appeared on my iMac with 27" Retina display.  It did not appear on my MacBook Pro.  Both were running LR 10.1 and Big Sur 11.1.  2.)  I was able to determine that the problem was the cursor display point on the iMac, specifically when the cursor was providing input such as moving a slider, changing the size of the crop box, etc.  The cursor indicator on the screen would stop moving, but it appeared the system was still recognizing the position of the trackpad or mouse.  (I tried both.)  When the cursor indicator briefly unfroze it would jump to a new position where the input had been, and then freeze again.  Hope that helps.

Been configuring the new MacPro which has the W5700X GPU. First off before it arrived I did a clean install of 10.15.7 on the MBP and migrated the production OS 10.14.6 to it. It was my intention to do a clean install of everything which I have a partition started but thought I would go ahead and use the migrated partition if everything was working ok. 

Now to the LR10.1 Library Module test on the migrated partition. An AOC monitor with the display profile was hooked up first and the test showed no slowness. Then hooked it up to my two NEC monitors that I normally use and selected the two display profiles from the old MP5.1 that appeared to cause the slowdowns. Still no change LR10.1 was as fast as before. just as fast 9.4. So I went and did a new calibration of both monitors and still no slow down.

Not sure what to make of this. Was it a clean install of the OS or the GPU making that much of a difference? Surly others have tried this. By the way the GPU history still shows no activity when in the Library Module, in fact what I found strange was compared with the GPU in the MP5.1 there was absolutely no activity in the GPU History. Make me wonder if there is not some not so kosher attempt at using the GPU for some reason going on when the slowness is showing.

@jsknick Absolutely no issues on this end but YMMV.

Yeah, don't go there, yet.

Any news for LR 10.1 and Big Sur 11.1 ?

Since I upgraded LRC to 10.1, LRC is running extremely slowly and occasionally crashing on my iMAC (2018) running Mojave 10.14.6. Frequent delays when scrolling and editing.  Even switching from Library to Develop.  And it hangs when I go between FIT and 100% on Navigator. Either LRC hangs, quits or the iMAC crashes. 

I just did the latest update for LR and I can barely get the tabs to slide. I’ve never seen it so slow. I get white squares across the picture like it’s still loading. When I logged on my iPad none of the changes were there and it crashed. How do I back this out?  It’s totally useless to me.