I had a similar problem using an Archer C2600. I was getting 90-100 Mbps on cable and 20-30 Mbps on wifi. I changed all the wifi settings to non-auto and now get 90 Mbps and above. On the 2.4 band:...

What I've found that works for me is to set fixed IPs for each device that I want to access later. Set the DHCP server to offer addresses in the range 192.168.1.100 to 192.168.1.199 Then, in the...