My sons Youtube uploads Kill the internet for the rest of the house. how to fix?

I have Four computers and a few handheld devices that connect to Comcast through a Netgear N600 (WNDR3700v3) router and then through a SB6120 surfboard cable modem. Specifically, My kids computers are hardwired into the router. Wife's and my laptops are wireless, as well as the handheld devices.

When the boy starts any kind of Youtube upload, he pretty much kills the entire internet for the rest of the house. What setting do I need to look into? Assuming there will be something on his Windows 7 desktop or in the router that can throttle his upload enough to allow the rest of us to connect. Just don't have any clue about these things.

Any help is appreciated and I will google it in the meantime.


Thank you,

L_S