I upgraded my Xfinity plan from 50 Mbps to 300Mbps after purchasing an SB8200 modem.
When the modem is connected directly to my computer, I get 300Mbps.
When the modem is connected to my router I get the speed of my old Xfinity plan: 50Mbps.
I am using two CAT5e cables, each of which, when connected directly from modem to computer get 300 Mbps.
I did a hardware reset of my router with no change.
My router: TP-link AC2300
Any ideas what might be going on?