Performance & battery · Heat and fans
Why did my fans spin up while Storage Studio was moving a big folder?
Short answer: A big move reads, writes and checks every file, so the disk and processor work hard until it ends — fans may spin up just as with any large copy. It's temporary; start big moves when you step away to avoid it.
A large move is real work: every file is read from your Mac, written to the destination and checked afterwards, so the disk and processor are busy until it finishes. On a Mac with fans, that can spin them up — the same as copying the folder in Finder would.
It's normal and temporary. Storage Studio still keeps your own apps responsive, and if the Mac gets critically hot it pauses its background work. If you'd rather avoid the noise, start large moves when you're stepping away, or let scheduled moves run during your Quiet Hours.
More about moves in Moving folders.