Downstream rate below BT checker results ...

It seems that after a recent migration my VDSL has a max rate of about 48Mb downstream(speedtest about 44-45Mb/s) - previously I used to be able to get speedtest results of about 52Mb/s. The BT checker gives a low(VDSL range B - impacted) rate of 54.1Mb down. Since my actual downstream rate is below the BT checker rate does this warrant further investigation by my ISP/Openreach? Link to BT checker results grab.

Short answer no.

It's the sync rate and not throughput (speed test) figures that matter.

An ISP migration is supposed to lower your speed, in almost all cases, unless already interleaved.
The DLM is reset to default interleaving and it can take a week or 2 for positive DLM changes to occur. Such as fastpath for ECI cabinets or G.INP and lower SNRM targets for Huawei cabinets.

edit: auto correct mistakes

2nd edit: your above the downstream handback, the important figure. Either way an engineer visit won't help. wait for DLM changes

Edited by j0hn83 (Mon 26-Nov-18 16:30:32)

To be clear my maximum sync rate(not speedtest) is now about 48Mb - resulting in a speedtest drop from about 52Mb to about 44-45Mb/s. Other ISPs give a guaranteed download(Ofcom) speed of about 52Mb/s for my line.

What other ISP's offer as a guarantee doesn't mean a thing.
Your ISP should have given you a range, and an absolute minimum guarantee. Only the sync matters for this.

As I said DLM can take time to get the line back up to speed.
How long can be narrowed down.
How long ago was the migration?
Do you have any line stats?
ECI or Huawei cabinet?

What did your new ISP quote at signing up time?

The maximum sync rate given in your router stats depends on the DLM settings, which change to defaults on migration. As you have already been advised. How long ago did you migrate?

I'm a little bit puzzled by this thread, unless you have migrated one of two connections and only need one to have FTTC now .

In reply to a post by RobertoS:

I'm a little bit puzzled by this thread, unless you have migrated one of two connections and only need one to have FTTC now .

Tis a long story I won't bore you with ...