If you have installed software that wastes computer resources on a regular basis, such as third-party Virus Scanners, speeder-uppers, Cleaner-uppers/Removers, Optimizers, third-party file Sync-ers such as DropBox, BackBlaze, OneDrive, or GoogleDrive, or a VPN that you installed yourself, it will do busywork at previously-impossible speeds — heating up at a ferocious rate.
This older junky software used to run as fast as it could, then would then have to suspend itself to wait for the disk drive to catch up before continuing to waste resources. With a faster drive, that drive-speed restriction is reduced. In many cases it still does not show up as using a lot of CPU, because it is doing a lot of intensive I/O, and not a lot of computing. That will still make your computer slow and heat up.