Recently changed over to FTTP service with BT on 1gb line but only getting about 500mbps to router (speedtest from GUI) and 300 (mutiple speedtests but mainly fast.com) or so to clients (cable and wifi).

When connecting PC direct to ONT and dialing it gets the 980mbps when testing so line and the cable in use appear to be fine.

I have been through the router and log shows WAN port enabling at 1000mbps to ONT so would have expected higher throughput when testing.

I have been through the router and disabled all traffic monitoring, QOS and anything else that would load router but no changes.

have rolled firmware back a few versions to see if this made any difference but sadly not so will update back to latest.

is there any other checks I can do before I just replace the device?