Laggy display with dual 4K+ monitors MacOS

[jhapeman1]

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.  

[Chrisjhood]

Yes thank you, I have been dealing with this bug for years ever since the 2019 (12 core, 192 gb,  pro vega II) mac pro was released. I never had this issue on the old trash can mac pro (6.1) only once I upgraded to the 2019 mac pro.  I picked up a brand new Mac Studio M2 ultra to test becuase i figured it was a GPU issue with my 2019 mac pro but same exact isssue on the brand new M2 Ultra stuido. All software uptodate and fresh install on Lightroom Classic and a new Catalog with 20 images in it located on the interal drive. Tested also with both 1:1 previews and with standard previews.

[JohanElzenga]

I can't reproduce this on my MBP 16" M1 Max with two 4K screens. If I set the secondary screen to loupe mode and the main screen to Develop, the sliders in Develop seem as smooth as always. The secondary screen does show a slight lag before the image is updated, but that does not significantly affect the sliders on the main screen in any way. Maybe if I did a thorough test I would detect a very slight difference, but certainly nothing that could be described as "the performance on the primary display degrades tremendously".

[jhapeman1]

Two external 4K screens on the Macbook Pro?  I should clarify I've tried with mixed screens, 4k and 6K or 4K and 5K; I need to reverify with dual 4Ks but that means moving some monitors aroudn to be sure.  It's not the secondary screen that ever lags (it does a little no matter what), it's the sliders on the primary screen, and the updates can lag as well.  For example, I'll move the exposure slider and it will "stick" and not move smoothly. 

[JohanElzenga]

Yes, I understand that, but as I said I cannot reproduce that with two 4K screens. The develop sliders are smooth as always.

[Chrisjhood]

I just tried my 14"M1 Max Macbook Pro with both 4k displays and 4k and XDR display, and I get the same issue.

Ive not tried a setup that I dont get the issue so I'm not sure how your not seeing any lag.

[JohanElzenga]

I'm not sure how/why you are seeing it...

[Chrisjhood]

Any chacne you can upload a short video showing no lag while in the develope and Loupe Modes?

Ive tried 3 diferent computer with different monitor set ups and as many new catalogs and preivew settings as I can think and every setup I experience the lag. Turn second screen to grid or off and it goes back to normal.

[jhapeman1]

It might have to do with the size of the files?  For example, I shoot with Sony A7RIV's and Sony A1's, so the files are all quite large.  I'm curious what files both of you are using?

[JohanElzenga]

Mostly uncompressed Sony A7R III files, so also not quite small (86.1 MB). I doubt this is relevant however, because Lightroom uses previews. Standard-sized previews (the ones used for loupe view) are based on your screen size, not on the size of the images. I have set these to 2880 pixels however, not to 'Auto' because there is a long standing bug where 'Auto' can generate huge previews depending on your screen settings. That may be something to check and try out.

[jhapeman1]

Interesting idea, but it's not the cause. I just made a clean new catalog and set it to use the same 2880 previews you do, and it didnt make a difference.  The sliders in the Develop module are still laggy.  I checked on my Mac Studio with two 6K ProDisplay XDRs.  I'll check on the 2 4K displays but I don't expect a change if Chris hasn't seen one either.  

BTW, I also checked on another Mac Studio Ultra we use here in my business thats connected to two Studio Displays (27" 5K).  Same laggy sliders issue there as well.  

[Chrisjhood]

Chagning the standard sized preivews def seems to make it better tho its still not fluid like it is if I put the second display to grid mode or turn it off all together.

[JohanElzenga]

Chagning the standard sized preivews def seems to make it better tho its still not fluid like it is if I put the second display to grid mode or turn it off all together.

By @Chrisjhood

Did you make sure you did a proper test? Lightroom will not change thousands of previews in an instant if you change this setting. It will probably change the previews only if and when needed. So set the size to 2880 pixels and then import a few new images so you are sure that these images will have that 2880 pixels preview size. Then do the test with these newly imported images. It might even be better to create a new test catalog.

[Chrisjhood]

Chagning the standard sized preivews def seems to make it better tho its still not fluid like it is if I put the second display to grid mode or turn it off all together.

By @Chrisjhood

Did you make sure you did a proper test? Lightroom will not change thousands of previews in an instant if you change this setting. It will probably change the previews only if and when needed. So set the size to 2880 pixels and then import a few new images so you are sure that these images will have that 2880 pixels preview size. Then do the test with these newly imported images. It might even be better to create a new test catalog.

By @JohanElzenga

Just created a brand new catalog with about 15 images i shot last night of the moon.  Changed standard preview size to 2880 before I imported.  Built previews on import.  Still have the lag.  Turn off second screen or turn it to grid and performace is fast and fluid again.

[JohanElzenga]

Well, then I'm out of ideas. I have no idea why this happens to you but not to me with a very similar setup.

[jhapeman1]

What resolutoin are you running the 4K displays at?  Full native resolution?  Maybe that's got something to do with this?

[JohanElzenga]

What resolutoin are you running the 4K displays at?  Full native resolution?  Maybe that's got something to do with this?

By @jhapeman1

Full native resolution would make menus and interface items tiny. I'm typing this on my iPad right now, so I can't check it, but I think I use something like 2560 pixels wide or a bit less.

[Chrisjhood]

I shoot sony a1 but when i go look back at old files from nikon d800 or d850 I have the same issue still.

[Chrisjhood]

It might have to do with the size of the files?  For example, I shoot with Sony A7RIV's and Sony A1's, so the files are all quite large.  I'm curious what files both of you are using?

By @jhapeman1

Just tried a new catalog with the standard size preivews at 2880 with some Nikon D800 files and still the same issue.  I dont think its the size of the files. Theres something not right with graphics perfomance when in this mode.

[jhapeman1]

Just to reply in a cleaner thread.

1) I have now tried this with two 32" 4K displays on my M2 Ultra Mac Studio.  Same problem.  It's easily repeatable.  It is *less* laggy with the two 4K displays than two 6K displays.  

2) Same with two 27" 5K Apple Studio Displays and two 6K Apple ProDisplay XDRs.

3) I tried using smaller-sized previews, and made sure they were imported into a clean new catalog so the previews and/or the catalog were not the issue. Still there.  No change.

4) I tried it on a PC and this is...interesting.  The PC in question is brand new, as in yesterday.  Top of the line Intel core i9-13900K 13th generation processor, 64GB of RAM and an Nvidia Founders Edition RTX 4090 graphics card.  Two 4K displays and there is a very subtle lag in the sliders.  If I wasn't testing this I might have not even noticed...but it's there.  

I don't have adapters for the 5K and 6K Thunderbolt displays to try them on the Windows PC, but I just ordered a pair from Amazon to try this out.  It will be interesting to see if they cause the same issue on the Windows version of Lightroom. 

[Chrisjhood]

Intesting, curious to see what happens when those adapters show up.

Ive tried 3 different comptuers, m1 max macbook pro, 2019 mac pro, m2 ultra mac studio tried with mulitple different display setups -- 2 4k, 4k and 6k, XDR and Studio display, XDR and 5k, 4k and 5k with new calotogs, fresh install of the OS and Lightroom, and different settings for previews and all still have the same lag issue in the develope and loupe.

[Chrisjhood]

Try the new cables?

[jhapeman1]

They didn't arrive yet.  

[Chrisjhood]

Try the new cables?