I have an Archer C900 set up as a router from my ISP modem. I also have an older Apple Airport Extreme attached via Cat6 cable used as an access point. I have the AP and a TV hardwired to the Archer, and another TV hardwired to the Airport through Cat6 cables. Everything was working great for weeks, then suddenly I am getting much slower speeds on the router, including the devices hardwired. I am getting about 40mbps on the 2.4 ghz network both via ehternet and wifi on the router, and about 240mbps via wifi on the Airport. In addition, the 5G network is almost useless, getting about 2mbps. My suspicion is that my son is running some sort of software to circumvent our time restraints that shut off his access at bedtime, as we set up the 5G guest network specifically for his devices and his gaming. He says we may have a ddoS, but I have those blockers enabled on the router. It just seems fishy that the 5G guest network is all he has access to, and the 5G network both for the regular wifi and the guest network seems to be all that is affected. In addition, we have about 10 wifi devices on the network at any time, but only 2 of those are phones. The rest are outlets and a printer, so I cant imagine it's bogging thenetwork down.