Performance & battery · Staying light on your Mac
Does Storage Studio's background indexing work like Spotlight?
Short answer: Yes. Its background indexing stays quiet while you work, speeds up when your Mac is idle, gives your own apps priority on the disk, and pauses under heavy load before resuming on its own.
Yes, it behaves much the same way. Storage Studio's background indexing stays quiet while you're actively using your Mac, speeds up when the Mac is idle, and pauses altogether when the Mac is under heavy load or in the lighter performance modes — then picks back up on its own.
Its background disk reading is also marked as low priority, so macOS lets your own apps go first when both want the disk at the same moment.
Because of this, sizes and profiles can take a little longer to fill in on a busy Mac. That's expected: the information arrives in the background, and nothing you're doing waits for it.
See also why a folder can still be measuring.