During a Q&A session on IGN Microsoft were asked how long it will take to download the day-one patch for the Xbox One. Marc Whitten, chief platform architect for the Xbox One, replied by saying:

“We are optimizing Xbox One so that the day one update is as fast as possible. While we’re still finalizing the details, we expect that the download will take between 15 and 20 minutes for most users.”

It’s unclear what Microsoft is assuming the average download speed of their users actually is, but regardless that seems to be a pretty hefty download. According to reports in August of this year the UK’s average Internet speed was 14.7Mbps, however the stats backing this up include just over 2,000 homes, some of which were using fibre-optic and others not. Realistically we can assume that the average speed is quite a bit less for most people. Still, let’s take that supposed average speed and do some basic napkin maths: assuming your speed download speed was maintained at exactly 14Mbps for 20-minutes, that would equate to nearly 2.5GB.

This massive update is in direct response to the public’s reaction to the Xbox One’s initial announcement, hence it’s rather sizable nature as the patch needs to remove the 24-hour check-in, allow Kinect to be unplugged etc.

Keep in mind that the update will be mandatory.  If you refuse to download the update then the Xbox One will have all of Microsoft’s original policies in place, including a 24-hour Internet check-in, which if not done stops you from playing your games.