30 Seconds to move between images in Develop

[WS007]

I have a problem with LRc on my Macbook Pro M1 (32 GB RAM/ 2 TB SSD): everything is running extremely slow. Changing from one photo to another takes e.g. about 30' in the "Development" module. The slowness applies to almost everything. It was not there from the beginning, but gradually increased within the last few months...

The Adobe support is underground: first one has to talk to a robot until the robot decides to give over to a human. The humans are little better, as they give general place paste/copy suggestions and refer to websides that are acessible anyhow, but all these suggestions do not help. Needless to say they fade away shortkly afterwards... . No advertisement for the expensive subscription 😞

I read here in the forum that the slowing down of LRc seems to be a common problem with Mac OS, but could not find a real solution. I wonder whether someone has found the problem and how to fix it. Below the system info...

Wolfgang

Lightroom Classic version: 13.4 [ 202406181129-60d181b7 ]
License: Creative Cloud
Language setting: en-AT
Operating system: Mac OS 14
Version: 14.5.0 [23F79]
Application architecture: arm64
Logical processor count: 10
Processor speed: NA
SqLite Version: 3.36.0
Power Source: Plugged In, 100%
Built-in memory: 32.768,0 MB
Dedicated GPU memory used by Lightroom: 7.724,0MB / 21.845,3MB (35%)
Real memory available to Lightroom: 32.768,0 MB
Real memory used by Lightroom: 4.274,7 MB (13,0%)
Virtual memory used by Lightroom: 417.249,2 MB
Memory cache size: 165,8MB
Internal Camera Raw version: 16.4 [ 1897 ]
Maximum thread count used by Camera Raw: 5
Camera Raw SIMD optimization: SSE2
Camera Raw virtual memory: 1385MB / 16383MB (8%)
Camera Raw real memory: 1432MB / 32768MB (4%)

Cache1:
Final1- RAM:963,0MB, VRAM:5.702,0MB, DSC05714.ARW
Final2- RAM:469,0MB, VRAM:0,0MB, DSC05715.ARW
NT- RAM:1.432,0MB, VRAM:5.702,0MB, Combined:7.134,0MB

Cache2:
m:165,8MB, n:1.159,1MB

U-main: 83,0MB

Standard Preview Size: 2048 pixels
Displays: 1) 3024x1964, 2) 3840x2160

Graphics Processor Info:
Metal: Apple M1 Pro
Init State: GPU for Export supported by default
User Preference: Auto

Application folder: /Applications/Adobe Lightroom Classic
Library Path: /Users/ws/Pictures/Lightroom/Lightroom Catalog-v13-3.lrcat
Settings Folder: /Users/ws/Library/Application Support/Adobe/Lightroom

Installed Plugins:
1) AdobeStock
2) Aperture/iPhoto Importer Plug-in
3) Flickr
4) Loupedeck2
5) Nikon Tether Plugin

Config.lua flags:

[JohanElzenga]

BTW, you can use Lightroom Classic to illustrate this very nicely. While your 4K display is set to 2560x1600 pixels, open Lightroom Classic and go to Catalog Settings - Previews. Check what size the standard previews will be if you use Auto. What you will see is 'Auto (5120)', even though the native resolution is only 3840 pixels.

Another way to illustrate it is by making a screenshot of the entire screen. Open it in Photoshop and check the size. It will not be 2560x1600 (the system settings), not be 3840x2160 (the native screen resolution), but 5120x3200 (double the system settings).

[Lumigraphics]

On my 2019 MacBook Pro, native resolution is 4096 x 2560.

With it set to 2048 x 1280, screenshot is 4096 x 2560.

Set to 1536 x 960, screenshot is 3072 x 1920.

Set to 1792 x 1120 (default), screenshot is 2304 x 1440.

I'd have to test on my M1 to see how scaling works there.

Sonoma 14.6.1

[JohanElzenga]

Yes, but you test it at resolutions lower than 50% of the native resolution. It seems MacOS cannot cope with that very well and only scales up by doubling it (it should do more than doubling it to get a crisp view). To mimic what I explained for a 4K screen, set it to something higher than 2048 (50% of the native resolution) and lower than 4096 (it might only be possible to do this with a special utility like SwitchResX). That would match the example I gave for a 4K screen that is set at 2560 pixels. (See my remark about that screen in my next message)

BTW, this is something I have been complaining about with Adobe for years. Unfortunately they do not seem to be able or willing to do something about this. Think what this means for viewing images at "100%". You would think this means that one image pixel is displayed on one screen pixel, but because of this upscaling trick that is not true. What happens is that Lightroom displays the image at 100% on this virtual 5120 pixels screen if you have set your monitor to 2560 pixels. Those 5120 pixels are then downscaled to the native 3840 pixels, so you are not looking at a 100% view at all... You will only see a true 100% view if you set the monitor to 1920 pixels (or 3840 pixels, of course).

[Lumigraphics]

Interesting topic on TidBITS.

https://talk.tidbits.com/t/non-apple-monitor-the-scaling-problem/25385/6

My current displays are the Dell U3011 and LG 24MD4KLB-B

[JohanElzenga]

I just checked, and the native screen resolution for a 2019 MacBook Pro 16 inch is 3072x1920 pixels according to Apple: https://support.apple.com/en-us/111932 That means the first two screenshot sizes are as I predicted, only the screenshot size when the display is set to 1792 is lower than expected.

BTW: One bit of advice: get SwitchResX or a comparable utility if you use a non-Apple 4K screen.

[Lumigraphics]

Apple supports up to 4096 x 2560 on my internal display. Everything is tiny and unusable but it works. Notive is 3072 x 1920. I have no idea how this works but it does.

[JohanElzenga]

Apple supports up to 4096 x 2560 on my internal display. Everything is tiny and unusable but it works. Notive is 3072 x 1920. I have no idea how this works but it does.

By Lumigraphics

I don't think it really does, because you can't display a higher resolution than the native resolution. If you could do that, then two screen pixels would somehow have to display three distinct image pixels, which is simply impossible.

What I think happens is that apps can send 4096x2560 pixels to the screen (and so a screenshot will also be that size), but this gets downsampled to the native resolution of 3072x1920 pixels when it is displayed. That's the same as the 5120x2880 pixels that are sent to a 4K screen when you set the screen to 2560 pixels. 

Here's a screenshot of what SwitchResX can do with my 4K screen. Do note that not every setting is HiDPI, so not every setting uses the downsampling trick. The difference is clear to see. If I set the screen to non-HiDPI 2560x1440 pixels, then the image is quite soft, because now the 2560 pixels are upsampled to 3840 pixels and you can clearly see that.

[Lumigraphics]

Nope, its showing me actual pixels. The panel must be above native resolution and scaled for default.

[JohanElzenga]

That's what I said. It is rendered above the screen resolution and then scaled when displayed. The screenshot will be above screen resolution because a screenshot is captured data that are sent to the screen, not an image of what is displayed on the screen. A screenshot will not show any dead pixels for that reason, and a series of screenshots will not get darker if you lower the display brightness between taking the screenshots.

[Lumigraphics]

This is what actually shows on screen. The display actually goes to 4096 pixels. Photoshop will not scale a panel at that resolution, it is showing actual screen pixels.

[JohanElzenga]

Sorry, but that is simply not true. Like I tried to explain, a screenshot does not show what is displayed on the screen, but what is sent to the screen. Your screenshot does not prove anything, because it shows what Photoshop sent to the screen. Photoshop does not scale anything however, the scaling is done by the screen itself*. A screen simply cannot display more pixels than it has.

Maybe this extreme fictional example better explains it. Imagine a super small screen, with only two by two pixels. Could you sent this image to that screen? Of course you could, why not? Would a screenshot show this picture? Yes, it would, because a screenshot shows what is sent to the screen. Would this tiny screen display this picture properly? Of course not, because the screen only has four pixels.

* More correctly: the scaling is done by the software that drives the screen, so by MacOS.

[Lumigraphics]

I'm seeing what is actually on screen. I have the computer right here in front of me. The pixels are SMALLER when I choose that highest resolution. The screen is physically going to 4096 pixels. Its NOT just the screen buffer (and yes I know how that works. A screenshot basically just renders the buffer to a file.)

I'm guessing that Apple set the "native" resolution as something usable, because at 4096 pixels its really not. I did some searching and found other people who got that resolution so its not just me. I'm only using Sonoma, with no third-party screen control utilities. If I don't toggle "show all resolutions" then 2048 x 1280 is the highest shown, which makes sense if the panel is 4096 x 2560.

[JohanElzenga]

OK, fine. If you want to believe that a screen that consists of 3072x1920 physical pixels can display 4096 x 2560 pixels without these being downscaled to the physical screen resolution, then be my guest. I'm sorry, but I believe Apple when it says that your screen is 3072x1920 pixels.  If your screen was 4096 x 2560 pixels, then Apple would have said so. They are probably required by law to tell the truth, and they have no reason to downplay their specs and say the screen has lower specs than it really has. Somehow I find that not very likely...

[Lumigraphics]

My 2015 MBP is 2880 x 2400, but the max resolution is 1920 x 1200 (on Monterey, not Sonoma.). So yeah Apple does funny things with the display. I'm going to ask on the Apple discussions board to see what the heck is going on. But I tested, went through all of the resolutions and I can see the difference and it is scaling correctly.

[JohanElzenga]

It's normal for Apple to give you only those system setting resolutions that are actually useful. Setting the 2015 MBP screen to its native 2880 x 2400 pixels resolution would make all interface items so tiny, that this resolution would not make sense as system setting. For a long time Apple used 50% of the native resolution as the default for MBPs. At some point they decided to increase that (I don't remember when that was, but I think it was indeed around 2015 or a bit earlier).

[Lumigraphics]

In Monterey they only show available resolutions as icons, and not a list. This UI has changed since, I don't recall if it was Ventura or Sonoma, but now its simply a list. I'm guessing that there is some interpolation trick to force a higher resolution on a panel. It doesn't make sense to me but I can see the differences at each resolution.

[JohanElzenga]

List or icons is still available. Here's Sonoma with icons. Right-click on an icon to choose a list instead. Click the 'Show all resolutions' to get all resolutions that are supported, not just the default ones that are shown as icons.

[Lumigraphics]

I couldn't get the list on Monterey, only on Sonoma.

[JohanElzenga]

I'm pretty sure that all MacOS versions can show a list too, but I'm not sure how to do that in each version. It used to be holding the Option key while you selected it, if I remember correctly.

[GoldingD]

everything is running extremely slow. Changing from one photo to another takes e.g. about 30' in the "Development" module. 

Ok, first a few common inquiries

• Is this performance degradation seen in both the Develop Module and the Library Module, or just the Develop Module?
• How much free space in percent (yes %) on that MAC Hard drive? Looking for at least 20%, some say 25%
• In LrC /Preferences/Performance/ what is your Camera RAW CACHE Settings amount? Hopefully not the Adobe default of 5 GB
• Your Loupedeck 2 Plug-in, what version number?
• Your Loupedeck application, what version number?

[AlexJz]

Can you try updating to 13.5 ?

I had the exact same problem, and 13.5 is at least significantly better, it not completely solved.