Nighthawk XR500 slow wired connections

Wifi 480down 23up. Speedtest.net reads my speeds are correct at 480down 23up. But Fast.com and google speedtest both say 10mb. I can tell the difference too while trying to watch streams they constantly buffer, and I even tested downloaing a game on steam. It's very slow. But If I were to connect from PC to modem and not use the xr500 router. All 3 speed test sites show same thing 480down 23up, and a Steam game 800mb download happen in seconds vs 10mins. I even see the lag in game, People tell me im skipping. So somehow it's defaulting to 10mb download. This is really annoying me. I even bought a $20 switch That went between the modem and router. The connection was giving me my max speeds. But if I used wifi at all while using the switch to bypass having to hard wire into router. My wired connection suffered and caused it to buffer. Now the weird thing is. When I have Modem-Router-Cat6-PC The wifi is amazing and doesn't affect wired at all even though it's stuck at 10mb. My mind is blown at this point.