Hello,
The download files for The Sims 4 are altogether quite large, and the speed at which they can be downloaded is dependent on the speed of your internet connection. If you have a slower internet speed, then the files will take longer to download. One thing you can do is turn off any other devices using the internet, and any applications that are using the internet on your computer in order to try and speed up the download.
The Origin Great Game Guarantee can be used either within seven days of purchase or within 24 hours of actually running the game (so starts the moment you open the game, and not when you start downloading or installing), so you would still be covered.
I hope this helps and keep simming,
Cody
