My IP download profile is 29.23 Mbps, upload 2Mbps.
BT speed tester typically measures 20-24 Mbps (it went down to 6 for a while but that is a different issue). For the first week or so after the upgrade, the TBB tester agreed with this. Some other testers (eg broadbandspeedchecker.co.uk) still do.
Now, however, the TBB speed tester typically measures about 40% of this ie 8-10 Mbps.
When I had ADSL, the BT and TBB checkers used to agree pretty well on 2.1 Mbps.
What is the experience of other new fibre users?
Are these checkers measuring the same thing?