Let’s consider a “decent” Internet speed of 200 mb/a. That’s 25 MB/s so it’d take 1,600 seconds to download 40,000 MB. That’s 26 minutes, so nearly half of your time is gone. Plus there is always time spent doing something like “installing”, checking the files, or whatever other stuff needs to be done besides just downloading the raw content.

Also, you don’t always get 100% of your advertised Internet speed 100% of the time.