Windows 10
If you have Windows 10 connected to your network, it could be slowing you down.
Windows 10 has a feature known as Windows Update Delivery Optimization (WUDO). This feature was designed to help users get their software updates quicker, by using peer-to-peer sharing. This setting, when enabled, uses your Windows 10 computer to provide other Windows 10 users a portion of their download (like a bittorrent service).
The result, your Internet slows down while updates are being "shared" across the internet to other Windows 10 users.
How do you turn off Windows Update Delivery Optimization (WUDO)?
Go to "Start"
Select "Settings"
Select "Update & security"
Select "Windows Update"
Select "Advanced options"
Select "Choose how updates are delivered"
Under the section "Updates from more than one place", turn the toggle to the "Off" position.