It should not directly affect it. It can have huge impact on games because the game code will in effect get stuck in video processing and ignore the network.
Simple file transfers and things like speedtest should not.
Do you have a second machine in your house. Can you test file copies between them, you can see the rates on the resource manager network tab. Be careful many of these are in MBYTES. You could also load a simple program called IPERF on both machine. This is a old line mode command that is extremely simple. It pretty much only test the network and the drivers and is not affected by things like memery/cpu etc. You should see rates in the 900+mbps in both directions.
Was there any garbage "gamer" network...