Comment by Smoosh

Has anyone else used an IBM mainframe with a hardware 327x terminal?

They process all normal keystrokes locally, and only send back to the host when Enter and function keys are pressed. This means very low latency for typing and most keystrokes. But much longer latency when you press enter, or page up/down as the mainframe then processes all the on-screen changes and sends back the refreshed screen (yes, you are looking at a page at a time, there is no scrolling).

Of course, these days people use emulators instead of hardware terminals so you get the standard GUI delays and the worst of both worlds.