What is g-sync from a hardware point of view?

Question

Monitors

What is g-sync from a hardware point of view? Is it a separate module that "add-on" over the main driver? Or is it integrated into the driver? Or maybe it's firmware? How, from a hardware point of view, do monitors with this feature differ from monitors without it?
And, if this is a module, where can I get this module? (Where do monitor manufacturers buy modules? Not directly from nvidia though.)

ps "driver" means "LED matrix driver board", not software

Answer 1

Nvidia G-Sync .