I've having a strange issue that I can't figure out what's causing.
Using a WRT1900ACS with stock 18.06.1. I have 100Mbps down from my ISP and can't seem to get over 9Mbps on clients that AREN'T tunneled through OpenVPN.
From OpenWRT router to ISP provided modem, I can get the full 100Mbps running speedtest-cli directly on the router.
But from a wired desktop attached to WRT19000ACS, I can't get over 9-10Mbit.
So I know my connection to ISP modem is fine, because the router can do it by itself, I can also get a full gigabit on client to client on LAN with iperf, so I know the clients and wiring is fine. Once I try and go LAN => WAN, my speeds drop like a rock, but LAN => WAN through an OpenVPN tun0 is also fine.