iCloud Photo Library has been using 25% of my CPU for over 2 weeks now. It is very frustrating when trying to conserve battery life in class and I can't seem to find a way to stop it other than ending the process which is only temporary. I have left my laptop on the past 2 weeks and it's constantly doing something.
I have exactly the same problem on 3 diffrent Windows 10 laptops where I logged in under my icloud account. I can not tell exactly, but it started in December when I took a number of photos then got back home and noticed my laptop's CPU FAN constantly spinning.
Then I looked at two other laptops where i have icloud installed and after syncing all pending photos got same problem.
I also tried to delete all photos from the laptop and sync them again. The CPU usage was minimum during the sync process but then jumped to 15%-20% once the sync was completed.
I am using iPhone 11 Pro Max
iCloud Photo Library (32 bit) constant CPU usage.
