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乔
乔31502311yjf0
Participant
August 4, 2023
Question

After lightroom classic is opened, the cpu usage rate is between 90% and 98%, which is completely un

  • August 4, 2023
  • 2 replies
  • 598 views

It can be used yesterday, but today, after lightroom classic is opened, the cpu usage rate is between 90% and 98%, and it is completely unusable.

 

APPLE M1 ULTRA, macOS 13.4.1, has not been updated recently.

 

Thank you.

This topic has been closed for replies.

2 replies

Conrad_C
Community Expert
Conrad_CCommunity Expert
Community Expert
August 5, 2023

In addition to the features in the Identity Plate already discussed above, in Lightroom Classic there are various background operations that can do chores when nothing is happening, do you know if it makes any difference if these are disabled? Some include:

  • Replace Embedded Previews with Standard Previews During Idle Time (in Preferences / General) 
  • Generate Previews in Parallel (in Preferences / Performance)

 

Even then, there might be something else going on, because even those settings should not make a powerful M1 Ultra unusable. (I use a less powerful M1 Pro.)

 

Also, have you confirmed, in the CPU tab of Apple Activity Monitor, that Lightroom Classic is the only application using 98% of CPU? Or are other processes also contributing significantly to that?

乔
乔31502311yjf0Author
Participant
August 6, 2023

Yes, Lrc is the only software with abnormal cpu usage.

 

As I mentioned above, since I completely uninstalled LRC before, there were no longer any photos in the directory and there were no rendering issues. When I reloaded the folder, the CPU usage was even 120%.

Conrad_C
Community Expert
Conrad_CCommunity Expert
Community Expert
August 6, 2023

When CPU usage is high, does the Identity Plate display progress bars for any activities, as in the example below, and if so, what’s it reporting?

 

 

Also, how is the Build Previews menu set in the Import dialog box below? Because three of the four settings can normally cause high CPU usage until all new imported images have previews. CPU usage should drop after all previews and processing are complete for the last batch of images you imported.

 

 

quote

When I reloaded the folder, the CPU usage was even 120%.

By @乔31502311yjf0

 

Just to be very clear: If there is a real problem here, it’s that it seems to become unusable (frozen?). But the CPU percentages you are reporting are not necessarily a problem by themselves, because the reported CPU percentages — 120% and earlier 98% — are not unusually high, and are a small portion of your Mac’s total CPU power.

 

The reason is that macOS and Activity Monitor report CPU percentage so that 100% equals one CPU core. You have an M1 Ultra. The advantage of the M1 Ultra is having an unusually high number of CPU cores: The M1 Ultra has 20 cores (16 performance cores, 4 efficiency cores). Completely maxed-out CPU usage on a 20-core CPU would be reported by Activity Monitor as 2000%.

 

So let’s work out exactly what “120%” CPU usage means. If an M1 Ultra has 20 CPU cores, and Lightroom Classic CPU usage is 120%, then Lightroom Classic is using 1.2 cores out of 20. That means 6% of your total core capacity is being used. Just six percent.

 

So 120% CPU usage is not a problem at all. But if the Mac is becoming unresponsive, that is a different mystery to solve, because huge amounts of CPU power are still available.

 

(On my M1 Pro, building 1:1 previews was using 459%, or a little over half of the 8 CPU cores it has, but the Mac was completely usable.)

dj_paige
dj_paige
Legend
August 5, 2023

Version Number of Lightroom Classic?

 

Have you checked to make sure (confirmed by looking, not by saying I never use these features) that these features are turned off?

  • Sync to the Adobe cloud
  • Address lookup
  • Face detection

 

Also, confirm that your anti-virus is not scanning folders that contains your photos and is not scanning folders that contain your catalog file.

乔
乔31502311yjf0Author
Participant
August 5, 2023

My LRC version is 12.4, which should be the latest, because of the high CPU usage, I have completely uninstalled/installed twice.

 

Regarding the three features you mentioned, should I keep them off or on? Thanks.

 

    dj_paige
    dj_paige
    Legend
    August 5, 2023

    See what happens if you make sure they are turned OFF. Also check your anti-virus. Also make sure that LrC is not rebuilding the previews, that could use a lot of CPU and should cause a fair amount of disk activity as well.

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