High CPU when idle - tried usual suspects

[affectionate_Rose0D45]

I got a brand new iMac after my 8 year old one died. I moved my old LR catalog over and LR is slower than on my old iMac, even though the new one should have significantly better performance due to the faster CPU, more memory and SSD.

Using LR Classic 10.1 Build 202010011851. iMac 32GB RAM, SSD, i5 3.3GHZ 6 core, Catalina 10.15.6, no other programs running

CPU is constantly over 100% even when left idle for hours, and LightRoom is just sluggish, even something as simple as scrolling the text in the splash screen when I went to get the version number!
Have tried disabling and enabling graphics processor. Disabled face detection. No Plugins installed. Sync disabled.
All other software running much quicker, so I don't think it's a problem with the iMac or Macos.
Any other suggestions most welcome 🙂

[GoldingD]

following

[GoldingD]

Might not be exact match, but see;

https://feedback.photoshop.com/conversations/lightroom-classic/lightroom-classic-user-interface-slow...

If it is, add yourself to the discussion.

Recommend you include your sys info.

[affectionate_Rose0D45]

Thanks @GoldingD I'll take a look.
It's just a tad annoying to get a new computer, new version of LR and then it's as slow as treacle. It seems quite common, so Adobe must know what is hammering the CPU like that. Apart from that I think LR is such a great tool 🙂

[Ian Lyons · Accepted solution]

You haven't mentioned which version of the iMac you moved from or to. You did, however, indicate that the old iMac was 8 years old, which would put it before the 5K versions released in late 2014. If this is the case, and your new iMac is 5K, then the  reason for seeing 100% CPU may be due to the application updating the previews in background. 

[affectionate_Rose0D45]

Thanks for that Ian. I went from a 27" late 2012 to a 27" mid 2020 iMac, so yes the old one was pre 5k and the new one is 5k.

After leaving LR running for a few days, and not allowing the iMac to go to sleep, it appears now to have finished what it was doing and LR is now usable and the CPU levels are more normal. So your suggestion is possibly correct.
I had unchecked "Generate Previews in Parallel", as I thought that would stop it trying to create previews when I was using LR, but that didn't seem to be the case.

If your suggestion was the answer then I wish LR would be less aggressive in generating previews so that the application is actually usable, or that it would give you some indiciation of what it was doing so you could leave it until it was finished.