Make a copy of your vault folder and open it as a vault in Obsidian. Does it have the same problem?
(After backing up) Try deleting or renaming config files 1 by 1 and restarting the app (I think Obsidian will regenerate ones that are missing, but you may want to research that). Does the behavior persist?
(After backing up, of course) Try removing other files 1 by 1, in case Obsidian is for some reason hung up on indexing one of them. As a first rough cut, you might remove all non-Markdown files, and if that has no effect put them back and try removing all Markdown files. If 1 of those does something and you have folders, you could get more granular by removing folders 1 by 1.
Testing config files one by one might make sense but on the other hand, I observe the problem with several of my vaults. They are completely separate. They don’t share files and are not nested inside each other.
Just now, I opened some random folder as a new vault. So this is a brand-new vault with standard settings. No community plugins enabled (safe mode=on), not too many files inside (1,361 to be precise, with only 2 Markdown files).
After opening the vault, CPU usage of Obsidian.app stays around 80% for a couple of minutes, then drops to near-zero.
This pattern repeats every time I close and re-open the vault.
I am more and more convinced that Obsidian does some initial indexing whenever a vault is opened. The larger the vault, the longer it takes. (One of my vaults has 60,000 files inside, of which 2003 are Markdown files.)
Edited to add: I do not refer to the one-time initial indexing that Obsidian does with brand-new vaults. It must be something else that happens at every start of a vault.
Yeah, I’d expect it updates the index whenever you open a vault (because you could have changed the files while it was closed). I normally leave mine open all the time. I closed and reopened it and saw CPU go pretty high, settle at around 40%, then go back down, all taking about half a minute (this is on an M1 MacBook Air).
Maybe there is something here to explore?
That does look excessive (to not-an-Obsidian-developer me). And the I/O on the earlier pics you posted goes up to almost 1 GB.
Oh yeah, I forgot to mention that my vault has 6,000 files (mostly Markdown).
I would hope that your computer should be able to handle Obsidian without much trouble (I was thinking you might have an old Air; anyway I realized that I won’t have much insight into normal performance problems).
I’ll try putting my vault on my old Linux machine to see what happens, but I don’t know when I’ll get around to it.