We had a power cut the other day, Thursday 29th. Ever since we've been getting incredibly slow broadband speeds, although the router is now reporting speeds in excess of 18Mb... which according to the ADSL checker is faster than we can expect.
I know it sounds peculiar to complain about increased speeds, but from previous diagnosis of problems on this line, the faster the router tries to sync, the slower the connection actually is... something to do with noise. The previous calls we've had determined a 'sweet spot' at about 14Mb with an SNR at about 6db i think... could be wrong, might be 9db.
Anyway, i think we're back to trying to 'max out' the connection, since the powercut - although i note we also seem to be IPv6 enabled now, which is new since Iast checked the connection. Can't see how it wouild affect overall speeds, but it is a change... and one that has not been articulated by BT.
I forget the protocol for getting my connection looked at, I think its post the speed test and ADSL checker results and the router stats page?
Re: Broadband Fast, But Actually Slow Since PowerCut
Based on the line attenuation the max data rate is correct but the data rate of 17.34Mbps down looks high if the snr is 9.1db but that may because that is the snr at that precise point in time rather than when the router rebooted. I don't have a HH6 but there should be somewhere in the stats something called WAN which may show the snr when the reboot occurred.
Regarding the actual speed are you using Firefox as that understates the results. If you are try using Chrome or Edge to see what the results are.