I'm on the Spark Max Fibre Plus plan and was previously seeing speedtest.net results in-line with expectations eg 700/500Mbps.

After a change in network setup today, I'm now consistently seeing a very symmetrical 145-165Mbps ie upload being the same or very slightly higher.

Here's my original setup (all connected via ethernet, though both routers were providing wireless AP):

ONT -- ASUS RT-AC68U -- TP-Link Archer C7 v1 -- PC (speed tests run here)

Unfortunately the AC68U died this morning, so it's been removed from the equation and the Archer C7 is now the primary (and only) router.

Its existing firmware didn't appear to let me do VLAN tagging, so I flashed the latest OpenWRT to it and managed to get connected successfully.

Everything else seems to be good ie wireless, DHCP, etc - just the speed has dropped off significantly. 

Any troubleshooting suggestions would be greatly appreciated.

Thanks!