if you've not seen the other thread about lack of 'upgrade' speed have a look round for it
Seems there are some issues depending if you run one of the software firewalls
I had same thing could only get 2.8 ish on my upto 4mb line - removed zone alarm, now up to 3.9 !!!
Trying others now
Sunbelt Keio4 I found even worse - down to .8mb !!
This thread I meant