Powerline network works absolutely flawlessly up until my brother wakes up and turns on his PC. As soon as there is more than just my PC on the network, I experience packet loss and ping spikes. It seems to scale with how much bandwidth he uses. When downloading a game at the full 80 Mbps bandwidth of our network, I experience about 33%-50% packet loss, with ping spikes in the hundreds to local servers. When it's video watching, I tend to sit at about 0%-2% packet loss and a ping that's about twice as high as it should be.

I have pinged the router when this happens, and even pinging the router drops packets and has ping spikes upwards of 30ms. The powerline network is currently an AV600 plug connected to the router, a TL-WPA4220 downstairs, and my brother and I each have an AV500 plug. As I said, this works fine up until he turns on his PC. This never used to occur, so I'm not sure what caused it. I have tried repairing the plugs, but to no avail. I have adjusted QoS settings, but nothing changed.

Any help is appreciated.