Does 'lightning-fast' mean that the application will be light on the system or does it mean that it's well optimised but still demanding enough that you require

Does 'lightning-fast' mean that the application will be light on the system or does it mean that it's well optimised but still demanding enough that you require a modern computer? I'm asking because I like to use my laptop Acer Aspire One most because of the size and because it the incredibly good feeling keyboard. BUT the system is 32-bit and running Intel Atom which means that before VSCode moved away from 32-bit I could use it, but it would take some time to open and I wouldn't really call it writing in real time, if you know what I mean~ :D But I love the keyboard shortcuts and the multiple cursor functionality, which is why I stuck with it for as long as I could!