Lightroom is very slow

[Flash and Flicker]

Hi,

I am using LightRoom and it is very slow. Earlier my profile was 2 yers old and now I created another profile but still is very slow. Photshop work fine. I copeid my system info. Anyone could please find issue?

Lightroom Classic version: 14.5.1 [ 202508231203-c2638d01 ]
License: Creative Cloud
Language setting: en-US
Operating system: Mac OS 15
Version: 15.5.0 [24F74]
Application architecture: x64
Logical processor count: 16
Processor speed: 3.8GHz
SqLite Version: 3.36.0
Built-in memory: 16,384.0 MB
Dedicated GPU memory used by Lightroom: 10,830.2MB / 8,176.0MB (132%)
Real memory available to Lightroom: 16,384.0 MB
Real memory used by Lightroom: 4,561.6 MB (27.8%)
Virtual memory used by Lightroom: 55,744.0 MB
Memory cache size: 1,100.9MB
Internal Camera Raw version: 17.5 [ 2318 ]
Maximum thread count used by Camera Raw: 5
Camera Raw SIMD optimization: SSE2,AVX,AVX2
Camera Raw virtual memory: 3078MB / 8191MB (37%)
Camera Raw real memory: 3370MB / 16384MB (20%)

Cache1:
Final1- RAM:352.0MB, VRAM:0.0MB, 0Y6A6528.CR3
Final2- RAM:562.0MB, VRAM:950.0MB, 0Y6A6521.CR3
Final3- RAM:352.0MB, VRAM:0.0MB, 0Y6A6522.CR3
NT- RAM:1,266.0MB, VRAM:950.0MB, Combined:2,216.0MB

Cache2:
m:1,100.9MB, n:1,057.0MB

U-main: 240.0MB

Standard Preview Size: 5120 pixels
Displays: 1) 5120x2880

Graphics Processor Info:
Metal: AMD Radeon Pro 5500 XT
Init State: GPU for Export supported by default
User Preference: Auto
Enable HDR in Library: OFF
GPU for Preview Generation: Auto (S5_7)

Application folder: /Applications/Adobe Lightroom Classic
Library Path: /Users/sushma/Pictures/2025_year_from_july/2025_year_from_july.lrcat
Settings Folder: /Users/sushma/Library/Application Support/Adobe/Lightroom

Installed Plugins:
1) AdobeStock
2) Aperture/iPhoto Importer Plug-in
3) Flickr

Config.lua flags:

[nikunj.m]

Hi, thanks for reaching out! 

You can try updating macOS to version 15.7 to check if that makes a difference. If not, you can try to reset the preferences of Lightroom using the steps mentioned here: https://adobe.ly/3W1g9aJ

Thanks,
Nikunj

[dj_paige]

Slow doing what? Please be specific and detailed.

[Flash and Flicker]

Editing of photographs, making mask, chaing exposure or any values. Takes too much time to export few images. 

[dj_paige]

Your GPU is 5 years old, and relatively slow compared to more recent GPUs, which can have an impact on your system which has a 5K monitor. As an experiment, try reducing the resolution of your monitor to something like 1920x1080, does that make LrC run faster?

[Flash and Flicker]

I am using this iMac since long time and it was working fine. Nothing changed.  Photshop work fine and this issue in LightRoom Classic only

[dj_paige]

And yet it is obvious that something HAS changed. The LrC code has changed. The operating system code has changed. You would be wise to try the experiment. Maybe your GPU driver has changed or is old and outdated, in which case you should update it. 

[Ian Lyons]

The System Info suggest the OP is using a Intel based iMac or MacBook. The following line in System Info needs further investigation as the system appears to be using more VRAM than is installed.

> Dedicated GPU memory used by Lightroom: 10,830.2MB / 8,176.0MB (132%)