Time with loads is pretty much a standard speedrun. You start the clock when you start the game, and you stop it when you finish.

Time without loads means that you take your total time at the end of the run, and then subtract however much time the game spent loading, so that it only tracks how long you actually had control over the game for. Usually it’s done for PC games with an autosplitter program that does this for you as you play.

Livesplit