Playing Diablo 3 Hardcore with Windows 10 Automatic Update
Honestly, Windows Update shouldn't lag your game, unless your internet connection is slow. I have a 256kB/s connection, and it doesn't seem to have any effect while playing games online.
If at all, Windows Update tries not to affect the speed of your any other connections to the internet while it's updating.
If you're really worried about Windows Update lagging up your system by downloading updates in the background, you can disable it by disabling the wuaserv service.
Note: You cannot disable it through the Control Panel or Settings App. The only way to do it is to go "under the hood".
This answer applies both to Windows 7, 8, 10 Home/Professional/Ultimate/whatever-fancy-name-they-use/Home Premium/Basic/Enterprise
- Open the services manager.
Try pressing Win + R then typing services.msc - Look for Windows Update (or its actual name, wuauserv) and right click on it.
- Select "Properties"
- Change "Startup Type" to Disabled in the Property dialog box.
- Select the "Stop" button if it is running and select "OK" to confirm your changes.
Windows Update uses BITS (Background Internet Transfer Service). This service is designed with several goals in mind, one of which is minimizing impact to other network applications.
Background transfers are optimal in that BITS uses idle network bandwidth to transfer the files and will increase or decrease the rate at which files are transferred based on the amount of idle network bandwidth available. If a network application begins to consume more bandwidth, BITS decreases its transfer rate to preserve the user's interactive experience.
https://msdn.microsoft.com/en-us/library/aa362708(v=vs.85).aspx
The landing page for BITS provides the link to its usage in Windows Update:
Note: BITS is most commonly used by Windows to download updates to your local system.
All that said, Windows 10 should not impact your network gaming experience.
If you are a bit more technically savvy then you can block inbound/outbound connections to the actual update websites:
http://windowsupdate.microsoft.com
http://*.windowsupdate.microsoft.com
https://*.windowsupdate.microsoft.com
http://*.update.microsoft.com
https://*.update.microsoft.com
http://*.windowsupdate.com
http://download.windowsupdate.com
http://download.microsoft.com
http://*.download.windowsupdate.com
http://wustat.windows.com
http://ntservicepack.microsoft.com
http://stats.microsoft.com
https://stats.microsoft.com
^ Source
You should be able to configure this within your OS but if not then the router-level would work just as well or maybe better.