pyronical: I am having this same problem... for over a year in this apartment, I've always synched at 11mb/1mb, yesterday I was getting 3.5mb/700k and now I'm getting 5mb/750k... seems to change every time I reboot my Genius modem.
Nothing has changed on my end.
Where exactly are you located and are you on a ULL or wholesale connection? Have you been recently cabinetised?