With a focus on minimising disruption, downtime is typically scheduled to begin at 1 a.m. PDT/4 a.m. EDT/9 a.m. GMT and last for an average of 2-3 hours.
it depends on your disk on the computer. ssd disk is the best option. It also depends on the speed of your Internet and the region where you live. Personally, I downloaded Fortnite in 1.5 hours, and I was watching YouTube videos at the same time