>> the BT speedtester sits on BTs network and as a BT ISP user you probably have preferential routing to that compared to something elsewhere on the internet.
Youre correct...
Once you come off one of their Network you get hit by "shaping".
Ive repeatedly seen speeds of anywhere between 1.2 - 2Mbps on external speedtesters, but can record 6800kbps on the BTw performance tester.
I can then swap the login on the same line and get near 7Mbps on a PlusNet connection. (SSB 2 realms).
Testing seems to show that the amount of throttling can also depend on which PoP you hop on/off Colossus to the peer-point at so obviously indicating that the amount of "shaping" can depend on location.
Ilford --> Telehouse seems to be worst for me.. possibly Telehouse being one of the busiest for forward transit/peering on to the internet?
Shaping is in inverted commas - because Im not sure if thats the correct term....
ie getting only get 1200 kbps on http traffic - yet being able to open up more nntp threads to increase your speed isnt exactly what I'd call QoS. *
*Not sure if this situation is still correct since Ive not been around much the past few weeks.