"when the system is working smoothly things open and close pretty much instantaneously. That is, unless you get a pop-up message that momentarily freezes the OS

"when the system is working smoothly things open and close pretty much instantaneously. That is, unless you get a pop-up message that momentarily freezes the OS" The OS isn't frozen. OS 9 just didn't have preemptive multi-tasking. If the code for that dialogue box wasn't specifically written to hand control back to the OS, it wouldn't do so until you click it away. Yes, this was the state of Mac OS a full five years after Windows 95 came out. There's a reason why Apple nearly died in the late nineties.