It`s hard to say and depends on the cable companies setup. Like in my previous example at my parents house, 6pm - 8pm the whole neighborhood is online, teenagers on a myspace page streaming 6 videos at once, etc. So speed gets pretty slow. But because it`s semi-rural, I`m assuming the cable company is limited by the amount of bandwidth they can provide, thus cramming hundreds of users down a skinny pipe. It won`t necessarily disconnect you from the internet, requests may take a little longer and some streaming audio/video will be choppy at best. Reminds me of the dial up days.
Not trying to dissuade you from cable or anything, but it will come down to how the rest of the users on your pipe will play.
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