I have two computers on my network - a desktop and a laptop. Both are hardwired to my router. Yesterday I started a 500MB Windows update on my laptop.
My desktop was suddenly very unresponsive: the mouse was delayed, switching tabs in Firefox took 10-15 seconds, programs would take a minute to launch, etc.
It occurred to me that it might have something to do with my laptop downloading files, but didn't think that was possible. However, this morning I did one last update for my laptop. The second the download started, my desktop slowed down and the second it ended my desktop returned to normal.
Why would network traffic on my laptop affect the speed of my desktop?