choppy/laggy performance on a Mac with 2 screens

Report · Aug 26, 2023

Lightroom classic 12.5

Mac OS 13.5.1

This has been an issue since the 2019 Mac Pro came out and I have tested now on a brand new Mac Studio M2 Ultra as well.

The issue is when youre in the develop module on your main screen and in the seconday screen youre in the Loupe Normal mode the sliders dont move fluidly like they do when ever else and the edit when applied to the image on both screens is super choppy and delayed. I have called in many times about this issue and this last time the tech I was talking to could not replicate this issue on his PC with dual screens so it leads me to believe it is a mac only issue. I thought for the longest time it was an issue with the 2019 Mac Pro only but after buying a new M2 Mac stuido and testing that I expented the issue to be gone but it wasnt.

If you have grid selected on the seconday display while in develop on the main it works as it should and there is no issue. Its only when you have Loupe Normal mode on the seconday display.

Please take a look at this and see if you can fix it.

Report · Aug 26, 2023

This is fairly normal and happens on all platforms - not just Macs, It is happening because the secondary display is rendered from a preview image and not a live display like in Develop on the main display. The extra calculation of a preview makes it not as smooth. It is just fine (but noticeable less smooth) than with a single display on my M1 Max machine. It should still be usable quite well though but less smooth. To be honest I don't think the secondary display in Lightroom Classic is all that useful anyway and Adobe should really rethink how this is used.

Report · Sep 03, 2023

I don't know what you're seeing, but on the three Macs I've tried, it's unusable in that mode specifically. When I use grid mode on the secondary display, it functions as it should and is fast and responsive, but as soon as I put it into any loupe mode, its performance goes to crap.

I completely disagree. I prefer to use two screens whenever I can. The first screen I can keep in grid mode while I flip through and see a full-screen preview of the image on the second screen. I can quickly flag images that I can then go back through to edit those. When editing, I don't necessarily need the two screens, but I still prefer having both screens. I can obliviously switch to grid mode on the second so that my editing isn't affected but then if I want to go back to the grid mode on the main display it won't let me because I have grid selected on the second display.

Report · Oct 17, 2023

Oh, sorry: should have mentioned it's a very well specced Mac Pro 2019 with discrete dual Radeons and SSDs + 128GB RAM.

Report · Oct 17, 2023

@Jao vdL your comment is confusing. I'm with you 100%, @Chrisjhood: I just jumped back into a test of the latest updated Lightroom Classic, as this bug was enough to force me to switch to Capture One over a year ago. Capture One is developed by a crew with way smaller resources than Adobe, and yet it uses two monitors perfectly well. You loupe/preview on the second in Capture One for the details, and edit the exact same RAWs on the first, with silky smooth, lightning quick performance. It's unacceptable for Lightroom, and it really does makes it unusable. One can only asssume it's a serious - and truly inexplicable - performance bug that Adobe really should have fixed ages ago. FYI I have read every way to optimise the LR catalogue and performance settings (with Captrue One, it just works perfectly out the box). Until then, I have no choice but to stick with Capture One (at least I have the perpetual license version in the meantime).

Report · Oct 17, 2023

I actually agree. Was just trying to explain why it is so slow and why I stopped using it. The secondary display is not well done in Lightroom Classic (there is not even an option in Cloudy). It is rendered from jpeg previews and therefore is very slow to update. In the main screen there is a direct pipeline to the raw data instead which is much faster than having to render a new preview every time. I would guess that fixing this would need a significant rework of the code behind the secondary display as it would need a completely different rendering pipeline that is much closer to the one used in the develop display instead of what is now used, basically the pipeline for Library display. Not excusing it though. I wish this performed better. On my M1 Max machine it is by far not as bad as you make it sound but it is still not instantaneous and as smooth as the main display by far.

I think you would probably be surprised at how small a team is actually actively working on Lightroom. Adobe is a big company but Lightroom is only a small part of it. They definitely have to prioritize what they spend time on.

Report · Oct 17, 2023

I think you would probably be surprised at how small a team is actually actively working on Lightroom. Adobe is a big company but Lightroom is only a small part of it. They definitely have to prioritize what they spend time on.

Sounds like your M1 has better graphics than 2x discrete Radeon Pros in a Xeon (Mac Pro) workstation! And it may well have. But as for having to prioritize, I'd guess if Adobe can be outclassed by Phase One’s 1-man dev team, Niels V. Knudsen (I am sure there are more now 😉 ), then they'd better make pretty basic functionality a priority – the option is right there in the open for a reason – or more customers will likely leave. 😆

Report · Oct 18, 2023

The graphics performance on these M1 machines is pretty astounding for how small and power efficient they are. In many things they will definitely beat dual radeon pros from that era. My machine runs AI denoise on a 45 MP raw file in 10 - 15 seconds. These machines are competitive with current era high end GPUs but at a fraction of the power usage. They're only beaten out by the highest end GeForce stuff really.

I don't know anything about the motivations of Adobe on secondary displays. My guess is that they know (the apps send usage feedback back to Adobe) how many people actually have dual displays and how many actually use Classic in dual display mode and have seen that that number is very low. The overwhelming majority of users likely is on laptops (and now mobile platforms) and only uses the built-in display. That is quite obviously true for the cloud based Lightroom but also for Classic. Of course that is a chicken and the egg issue. When performance is abysmal with a secondary display, people quickly give up on it.

Report · Oct 18, 2023

It really is quite frustrating; how and why did it work so well on the 2013 Mac Pro but hasn't worked since?

I really wish Adobe would look into this.

Report · Oct 18, 2023

Screen resolutions and image resolution are far bigger now than they were in 2013. If you were to run it on a machine with the screen resolution (1080p or 1440p instead of 4k or higher now) and the raw resolution common in 2013 (good resolution was 24 MP. Low nowadays is 45 MP), it would be quite a bit faster on a current machine driving those same displays and working with the same files as it was then.