That stretches the definition of silent. On MacOS you need command line utilities or third party software to observe throttling, but on Windows this information is easily viewable in the performance tab of the task manager, and Linux exposes this information in /proc.
Being buried away in technical debugging tools is 'silent' for 99.9% of users.
A common task that repair shops do to "fix a slow PC" is clean dust from the fans and heatsinks to reduce throttling. Users don't know or understand that this is happening, they just know their system is slow.
