P: Slow UI when using Mac and Custom Display Profile

My system is near identical to yours, so your tip is welcome. Fortunately, I do not rely on Lightroom for my living and even more, fortunately, I was able to roll back to the previous version, so the issue is not as serious for me as for many others.

Hello everybody! I must also share the problems I face with new Lightroom and some potential "releaf actions" untill a proper update will come out to solve the problem.

My system is:
Apple Mac Pro 5.1 (2012)
x2 CPU Intel XEON x5690 3,45GHz
96GB RAM
NVME SSD for Cataloge and Photos
AMD RX VEGA 56 8GB

My system works great with all other software except the new version of Lr Classic. It is so laggy I cannot work with it at all.

Before I share my potential releaf solutions I should mention that my computer used to work the new Lr Classic great with my previous monitor which was a 28'' 4K (DisplayPort connected).
Once I bought 4 new monitors 32'' 4K in order to review them and keep the best, I realised that all of them found so dificult to work with Lr Classic. So it has to be something about the UI of the software and how it scales itself to work on larger displays.

One releaf solution was to make Lightroom work in "Low Resolution". It seems to increase the performance. I made a video about that:

That way I can work with the new version (because all my cataloges are converted to the new standards and I cannot go back) a little bit faster. Nothing like compared to the snappy experience with my 28'' 4K monitor, but it looks better.

Another work around is if you work with a 4K 30+ inches display, to make Lr work on a smaller window and not full screen. Working Lr as Full HD on a 4K display seems to make the software run better. You can also try to lower the resolution of the 4K display to Full HD dimensions, but what's the point to have a 4K monitor then.

The only way I was able to work the new Lr Classic on Full Screen on my 32'' 4K monitor was with Lr running on low res (video above) and changing the Calibration to sRGB. Of course I am not feeling well working my expensive monitor on a non calibrated profile, but I hope it is just a "buying some time" solution to this problem.

I hope Adobe will come up with something stable next days!

@Sven

It's probably the same as running LR in Low-Res (Non-Retina) mode. 

I just noticed that my system shows a great boost in Library performance on my 4K BenQ SW271 with Adobe RGB color profile (calibrated using i1) when changing the display resolution to "unscaled full 3840x2160" in BigSur. Way better than any scaled resolution which I usually applied before.

I've been having similar issues as some identified. Develop module painfully slow, freezes my MacBook, unusable essentially unless you are doing only minor edits. 

I reverted back to V 9.4 and so far this seems to have "fixed" the problem, although it has created another, ie I can not use my most recent catalogue, LR won't let me open it, says the version is too new so I had to go back to an older catalogue and start the process of reloading my newer images. Bit is a pain, I'd say but at least now I can do my work.

Hi @ann_chown ! I would be surprised if any software developer of a resource-intensive app doesn't devote some resources to examining how efficiently they use them. The amount of RAM has a significant impact on performance, but it's not the only resource that has impact. One thing to note, though, it that while it may be the nature of current software tech to expand the size of RAM required with the addition/revision of each core feature, the way that computer operating systems & hardware are managing RAM use is changing for the better. As this article shows, it's one of the advantages of the new Apple M1 line (whose basic, entry-level options were released this year):

How 8GB RAM Overperforms in M1 Macs https://www.lifewire.com/how-8gb-ram-overperforms-in-m1-macs-5091929

Depending on your purpose & expectations, you may not need over 8-16GB RAM: performance is always a subjective thing. While others on this thread can't live with less than 32GB RAM, I've been happily using 16GB iMac 5K for nearly 4 years to run LR alongside other apps (e.g. mail, Chrome, etc.) as a hobbyist who did a few paid photography jobs. One of these was done on an old MacBook with 4GB RAM to use the latest LR & PS versions available in Jan 2017: I was forced to use this in an emergency because my main computer's motherboard died the week before I was due to deliver (it was painfully slow, but hey, job done). Tht experience taught me that there are things in LR that PS is much faster or offers a broader flexibility (e.g. cloning & healing).

If photo-processing/retouching is a business-critical element for you, you should have someone either on staff or as a consultant to provide you technical advice about all aspects of your hardware/software setup (from strategy to deployment, acquisition to resilience planning), once you set your subjective expectations (how long a job of a certain size should take to complete).

Worrying (or worse, whinging) about what any software developer is/isn't doing hasn't ever been valuable use of time: we accept what we can't control, plan for the unexpected, and work to suit. This sometimes means avoiding upgrading to the latest version of anything (OS or app) as soon as it becomes available, because one doesn't have the ability to test their impact without being able to withstand the consequences...

Lightroom Classic 10.1 brought my iMac late 2015 to a halt and forced reboot, and the crash disabled the Bluetooth keyboard and Magic Mouse II when I rebooted.  I've dropped back to LRC 10.0, which appears to work better.  Also, changed the monitor profile to Adobe RGB (1998) rather than a display profile generated by a colorimeter.  A Windows laptop with 16GB ram and a 4 GB graphics card seems to work better.   Photoshop on the Windows laptop (Dell Inspiron 2018) works fine and also seems to be okay on the iMac.   I've noticed that many of the people reporting problems were on iMacs from late 2015).

System information:

Lightroom Classic version: 10.0 [ 202010011851-ef6045e0 ]
License: Creative Cloud
Language setting: en
Operating system: Mac OS 10
Version: 10.16.0 [20B29]
Application architecture: x64
Logical processor count: 4
Processor speed: 3.2 GHz
SqLite Version: 3.30.1
Built-in memory: 24,576.0 MB
Real memory available to Lightroom: 24,576.0 MB
Real memory used by Lightroom: 6,007.4 MB (24.4%)
Virtual memory used by Lightroom: 12,135.8 MB
Memory cache size: 1,764.7MB
Internal Camera Raw version: 13.0 [ 610 ]
Maximum thread count used by Camera Raw: 3
Camera Raw SIMD optimization: SSE2,AVX,AVX2
Camera Raw virtual memory: 1516MB / 12287MB (12%)
Camera Raw real memory: 1525MB / 24576MB (6%)
Displays: 1) 5120x2880

Graphics Processor Info: 
Metal: AMD Radeon R9 M380

Application folder: /Applications/Adobe Lightroom Classic
Library Path: /Users/rebeccaore/Pictures/Lightroom/MasterCatalogAllCameras/MasterCatalogAllCameras-2-v10.lrcat
Settings Folder: /Users/rebeccaore/Library/Application Support/Adobe/Lightroom

Installed Plugins: 
1) AdobeStock
2) Aperture/iPhoto Importer Plug-in
3) ColorChecker Passport
4) DxO PhotoLab
5) DxO PhotoLab 2
6) DxO PhotoLab 2 Importer
7) DxO PhotoLab 3
😎 DxO PhotoLab 3 Importer
9) DxO PhotoLab 4
10) DxO PhotoLab 4 Importer
11) DxO PhotoLab Importer
12) Facebook
13) Flickr
14) HDR Efex Pro 2
15) Nikon Tether Plugin
16) ON1 Effects Standalone 2019
17) Qimage One

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@zobeleye 

32GB is plenty to run Lightroom well with only modest improvements with more memory. Don't forget what else you might be running concurrently that is using RAM, the machine needs to be sized for all concurrent resource consumption. 

With 16GB on a Windows machine, it runs quite well if only a few browser windows are open (Edge or Chrome but not IE or Firefox) and using Windows Defender instead of a 3rd party antimalware tool. 

@ann_chown 

As software becomes more functional, it steadily requires more resources. That is just the reality of software. Put 1,000 lbs in your car and notice how much it slows down. 

16GB should be considered a minimum while at 32 it runs really well. There are small improvements with even more. 

And while "genuine" Apple memory is really expensive, there are 3rd parties that make less expensive memory just as good as anything from Apple (never forget, Apple doesn't actually make anything). My favorite is macsales.com, and they include full installation instructions for your specific computer. We've been using their RAM on my wife's iMacs for years with zero problems. 

That is not it. 96GB and I see the same slowness with 10LR. The Library module in LR10 is not using the GPU.