Performance - From a Computer Science Point of View

Joel Weisbrod I just saw the video. This is pretty bad and definitely beyond standard LR slowness 🙂 It must be something in your hw/sw that LR really doesn't like. How is it without GPU acceleration? Seriously Adobe could run some debugging/diagnostics on your system to narrow down the issue.

Another challenge for the Lightroom team is that, except for the Camera Raw core, Lightroom is primarily written in Lua, an interpreted language. Imagine if Microsoft wrote Excel in javascript!

Within the Adobe applications, I think this is a unique approach, and probably was there from the beginning and never changed.

While the Lua text is converted to byte code, it is not a compiled language like C. Lua is supposedly relatively fast, but there still has to be a performance penalty there. Hopefully the Lightroom team has identified some of the critical areas and are converting those into a compiled language.

Hi Guys, I have first alerted Adobe on this slowdown a year ago, on this thread which was largely ignored. it was related to export speed being double the time after working on images compared to export the same batch after a restart.

https://feedback.photoshop.com/photoshop_family/topics/lightroom-image-export-is-much-faster-after-r....

I have also linked the performance degradation in export results to the general slowdown in image editing. its all stem from the same issue to my analysis and by doing simple export benchmark which I will outline below we can give Adobe simple performance data. Adobe can try and replicate it very easily in their high-end CPU test machine.

Here are the steps.

1. Select 30 images for export as full size add them to a collection called '30 images export speed test'
2. Open the task manager and put it on the CPU graphs 
3. Restart Lightroom
3. start the export and time it using your stopwatch on your phone.
4. you will notice the CPU shoots up to 100% on the first export
5. do a print screen of it if you want to post it here
6. once the 30 images have finished start the exact export again, without restarting Lightroom
7. Look the CPU graph and you will notice no more 100%, Lightroom is now slower.
8. Time it and take a print screen of the CPU graph if you wish to share it.
9. Do it again, and time it and see if it's getting even slower
10. Post your results here, with the OS, CPU/GPU type and No of Cores and type of Raw files

one big question is there anyone out there that the results are consistent with no performance degradation I would love to know their spec! 

here are my results for 

30 raw files of phase one IIQ 280 80MP
Windows 10, i7 5960X 8 Cores, Nvidia 980Ti, 64GB RAM

export times Lightroom Classic CC 7.0.1 in minutes per run in order
2:31, 3:17, 3:56, 4:35, 5:10

Here is the test again with the OpenGL instead of DirectX 
Config.lua flags: 
Develop.PreferOpenGL = true

2:24,3:12,3:55

Clear performance decrease in both scenarios, so the flag does not make any difference to performance degradation....

here are the CPU graphs 
1. first run CPU maxed to 100% most of the time 
 

2. second export CPU less busy export is slower
 

3. third export CPU even less busy and export is even slower

 
4. forth export even slower, I skipped the screenshot you got the idea ...

Here are the capture one 10.2 times for the same 30 images in minutes
1. 1:17 
2. 1.16
3. 1.17
4. 1.16
5. 1.17

here is capture one CPU graph which you can see there is plenty of CPU to keep working on images while the export is running at consistent speed, no performance degradation after 5 runs.


Capture one puts Adobe to shame.

Its frustrating Adobe put their resources into lightroom cloud instead of fixing this year-old bug.

Anyone who can do this simple test and let us know in which specs there is or isn't performance degradation so we can narrow our understanding for the reasons behind this problem.

I'm using DirectX as well as it is the default and when I used the suggest flag above the system show exactly the same performance degradation.

also, the sliders are slower, so I'm better off with DirectX.

Okay, I confirmed that I am now using OpenGL.

I am testing this on some RAW images with only minor changes applied as a preset when they were imported. (Lens Correction, Black Clipping, Vibrance, Clarity, Small Amount of Sharpening, Small Amount of Noise Reduction).

It is definitely different in that some things seem faster and then a few images later they seem slower. Cannot really pin it down but it is still too slow for any serious work.

With one monitor, it definitely is better since as soon as I activate the secondary window, it dies completely while this did not seem to change things with DirectX.

The movement from image to image in Develop seemed faster with one monitor and with two it is extremely slow.

Slider interaction with the image preview and histogram was slow but usable until I turned on the second monitor.

Turning off the second monitor did not improve the performance any.

Here is a video documenting the poor performance.

Good idea Fred but no cigar!

Joel,

At the moment, the following flag will force LR to use OpenGL.  Interested to know if that helps any.

Config.lua flags: 
Develop.PreferOpenGL = true

I am using DirectX. Not my choice but it seems it was chosen by LR.

For those of you on Windows (10) who are experiencing slowdown problems after editing some number of images in Lightroom - are you using DirectX or OpenGL with Lightroom?

Hi Assaf,

thanks for sharing your experience. I'd like to repeat the steps suggested by you, but just to make sure: how do the export-settings look like you used? Do you export as JPEG - and if so: at which compression level?

And just to add some personal experience here: For me Lightroom Classic doesn't perform better. Actually I have the impression it get even worse in some areas, for example when making exzessive use of the Adjustment Brush. In such cases LR slows down dramatically with every new picture I'm working on. Finally I'll have to restart LR.

Sorry .. I meant I am experiencing performance issues. See my earlier post in this thread.