Windows NT on 600MHz machine opens apps instantly. What happened?

It blows my mind how unresponsive modern tech is, and it frustrates me constantly. What makes it even worse is how unpredictable the lags are so you can't even train yourself around it.

I was watching Halt and Catch Fire and in the first season the engineering team makes a great effort to meet something called the "Doherty Threshold" to keep the responsiveness of the machine so the user doesn't get frustrated and lose interest. I guess that is lost to time!

I was just reading this week about someone trying to get their UHK keyboard to launch an application on Windows by producing a sequence of keys starting with the Windows key. They needed to put in a delay to get this to work, and it reminded me of my frustrations launching programs in Windows as the start menu takes its sweet and variable time. Not least because I know the technology has been focused on getting adverts into the start menu.

This is partly an OS design issue. There's no deep reason the OS should ever throw away keypresses, but contemporary GUIs have a very weak and flaky notion of focus. Contrast this with mainframe apps where users could learn to go incredibly fast, because keystrokes were buffered per connection and the mainframe would process them serially, so even if you typed faster than the machine could process them it wouldn't matter, no keys were lost.

Mainframes don't buffer keystrokes at all: rather, they send a screen to the terminal with marked "fields", and then the terminal handles all keystrokes until you press return or one of the attention keys to submit the changes back to the mainframe. Thus, even on a heavily loaded system, typing is instant because the main CPU doesn't get involved at all