In reply to a post by j0hn83:

What does the BTw DSL checker quote you under the downstream handback threshold column?

VDSL Range A (Clean) 42.4
VDSL Range B (Impacted) 25

Can you expand on this info please?

As I understand it that's the figures at which Openreach will let the ISP out of their contract, and refund any charges. I'm not 100% sure on when they use the clean or impacted figures. Looks like Talktalk are quoting you the impacted figure.

I recall reading something along the lines of, if you have a managed install (with an engineer testing the line) then they use the clean figures. If it's an unmanaged install (self install, no engineer) then they use the impacted figures. I can't recall if that was for the downstream handback threshold or just for an ISP quoting estimates. Don't quote me on that I might have read it on the back of my Coco Pops box.

Ultimately talktalks service would have been equally as fast as the more expensive one you have chosen.

When they quote 25Mbps they're just quoting the lowest number on the BT estimate which makes sense as some people will end up at the lower end of the estimate. The vast majority will be much faster nonetheless.

The impacted speed accounts for cross talk and a poor setup.