Advice for DSL Users with Windows 10 and Suddenly Slow Internet
(Updates added to the bottom of article)
DSL users may find that their Internet connection seems much slower once they have upgraded a computer to Windows 10, or purchased a new computer with Windows 10. This may be due to Windows 10 downloading updates
or sharing updates using what Microsoft calls Windows Update Delivery Optimization.
If Windows is downloading updates, it may affect your available bandwidth (Internet speed). To reduce the chance of this, it would be a good idea to Change When the Computer Sleeps, when plugged-in, so it does not “go to sleep” overnight.
To prevent the computer from sleeping when it’s plugged in (so that updates can occur overnight), go to Start [Windows logo], then Settings ⚙ > System, and then select Power and sleep. In the Sleep section, change the setting for, “When plugged in, PC goes to sleep after” to Never.
Then, leave the computer on, overnight, at least, for several nights after Microsoft’s Patch Tuesday.
Patch Tuesday occurs on the second, and sometimes fourth, Tuesday of each month in North America [Wikipedia].
This would avoid the computer downloading and installing updates while you are trying to use your computer, in the daytime. Instead, it should perform those tasks, in the early morning hours, while you not using your computer or Internet connection.
[Update] Starting with the Windows 10 Fall Creators Update (version 1709) Microsoft has added new options that allow you to limit the bandwidth your computer uses to download updates. Visit this web page [windowscentral.com] for more information and instructions.