One of the IBM 1401 computers (1959) at the Computer History Museum has hardware support for pre-decimal pounds/shillings/pence, to perform arithmetic on these values and print them. Thus, the computer has three fundamental datatypes in hardware: arbitrary-length strings, arbitrary-length integers, and pounds/shillings/pence. Of course there were two competing standards for encoding pounds/shillings/pence, so the front panel has a knob to select the standard.
(Before decimalization, there were 12 pence in a shilling and 20 shillings in a pound. Mathematical operations on currency were both difficult and extremely common, so IBM provided hardware support as an option. There were boards of transistors so you could add, subtract, multiply, or divide currency values with a single operation, rather than an inconvenient sequence of instructions.)
To get back to the original topic, I'll mention that my MacBook Air would drop keystrokes if I visited a website with, say, a video ad. I find it kind of appalling that computers in the 1960s could handle input from hundreds of keyboards at once, while a 2017 computer can't manage a single keyboard.
In the defense of your Mac, computers of the 1960's had terminal controllers for dealing with the communications. And 3270's were like web browsers - getting a form, sending the data back, getting another one - an excellent design for avoiding hardware interrupts ;-)
But yes. I've seen 370's with a good couple hundred 3278's connected and that thing was still quite snappy, even though the CPU in my watch can run rings around it. I guess even two VT330's would stress my current laptop if I could type on two keyboards fast enough ;-)
The widespread adoption of CISC architectures solved this problem, since many of them included special-purpose BCR (Binary-Encoded Roman) instructions.
The early 3rd century was the best era for Microsoft with Windows Severan.