Internet connection sharing help

[CHICKEN204]

I got two computers in the basement, my main computer internet is connected through Ethernet/router. while my 2nd computer internet is connected through Ethernet cable from my main computer 2nd Ethernet outlet. I went and check the internet connection sharing and both now internet. But whenever I play steam games on my main computer the second looses internet connection is there anyway to solve this? sorry for bad English its my 2nd Language.

Thanks

 

[failboat]

The easiest way is to get a 4-8 port unmanaged switch and plug all 3 wires into that or run another wire.