Cable internet speed.

I'm running cable for internet access, and for the last 6 months, or so, it has been extremely slow. I get a lot of emails in the form of newsletters, with links to the full stories. When I would click on a link sometimes it would take 7 minutes or more to load the entire page. I called the local cable company several times and they would suggest things to try to get more speed, but nothing worked. Then on Thursday, October 3rd, I called again. Talked to a young man and he suggested i do a speed test. I did, and it showed 11.15 meg down, and 2.09 meg up. He said the down speed was horrendous, that it should be 25. I then told him I was running Linux, not windows, so he suggested I try windows. I have a homebuilt computer with an MSI 64 bit, mobo, 16 gig of DDR3, a 1.5 terrabyte hard drive, an Nvidia 8400 512 meg video card, and an AMD 640 quad core processor. I have Win XP, Win 7, Peppermint Linux 4, and Mint Linux 15 on the hard drive. I opened Windows 7 and ran the speed test again. This time I got 6.05 meg down, and 1.7 meg up. He couldn't believe it. I explained to him that everything about linux is faster than windows. Anyway, he transferred to another guy and he was of no use either. He transferred me to paid support and this gentleman told me they could send someone out, but I would have to pay, and I told him I had already paid enough. I am paying for the Turbo tier, and am getting dial up speeds. Told him I would seek an alternative ISP. Well, Thursday afternoon I mysteriously started getting decent speed. Don't know what happened but the pages were popping in seconds instead of minutes. And so far it has held. Can't imagine what happened, because I have changed nothing here. but this more like what I expected of cable.