When you’re downloading updates for Windows, usually it comes directly from Microsoft’s servers which means that there is a finite amount of bandwidth Microsoft is able to allocate to you, especially when you consider that there could be thousands of other users looking to download the updates at the same time.
For the most part the updates are pretty fast although it seems that with Windows 10, it looks like Microsoft is finding ways to make pushing out updates even faster, and apparently one of the ways they’re looking at is to use some of your bandwidth. As you can see in the screenshot above, this is an option that you can choose to enable or disable.
There are two options for you to choose from. One option is that updates will be shared on computers and devices on your network, so if you have multiple computers at home, the update downloaded on one computer can be shared with the rest. The other option is to share the update with the internet in a way that’s similar to how torrents work.
According to a statement Microsoft issued to The Next Web, this feature basically “helps people get updates and apps more quickly if they have a limited or unreliable Internet connection”. It also apparently won’t slow down your internet connection as it uses a limited portion of idle upload bandwidth, but it’s something to take note of either way.