My Stong advice to all those that have been upgraded to 10Mb/s and are getting nowhere near that speed is to experiment with your upstream channel.
Start with Channel 1 and run 3 speedtests (from here:
http://www.adslguide.org.uk/tools/speedtest.asp) on EACH channel and note the downstream"true" speed value (the one with overheads)
Do the same for each channel and then see which channel is giving you the most consistent higher speed and then set the modem to it. This can be done from the modem control console.
If done during peak time then this will make sure you are getting the maximum possible speed when your node is under heavy use and will give you an even better value at other times.
Then max "true" speed value I have had since they switched it over yesterday is 10131 Kb/s and that was at 8:30 am this morning. At 1:27 am I got 9940 Kb/s