Stats seem to indicate you're connected at nearly full speed (74Mbps as opposed to 80Mbps), so that doesn't appear to be the issue (unless your connection keeps dropping and reconnecting at a much lower speed).
You haven't mentioned your IP profile (get this from doing a BT speedtest).
Have you tried a multi-thread download (grab the 1GB test file from the TBB site but download it using a download manager - Free Download Manager
will let you split into several parts simultaneous download - IIRC the TBB server allows the 1GB file to be split into 12 threads/parts for downloading).
As a rough indication, if I download the 1GB test file, from TBB, using Internet Explorer (i.e. a single thread download) my 80Mbps connection manages a little over 10Mbps.
If I download the same file, from the same server, but using a download manager (splitting the file into 12 parts) it maxes out my 80Mbps connection.
This, to me, indicates either BT is throttling (can't be congested as pings are fine, and pings are badly affected by congested ISP networks but not by throttled networks) or the TBB server is only able to upload each thread at around 10Mbps (which I highly doubt).
This will check to see if it's your overall connection/download speed which is poor, or whether you're somehow being limited on the download rate of each thread (some may call this throttling).
vDSL2 FTTC Infinity with BT
DL Sync 80Mbps
UL Sync 20Mbps
Edited by adebov (Fri 04-May-12 16:51:12)