The problem lies not with you speed, but that of your data source.  A faster connection would not solve your problem.  I have a 30 mbit connection and I too experience the same problem sometimes.   
Sometimes if I'm watching a video clip or tutorial in some applications, it stops and starts. I don't much about it but I guess the download has to build a certain buffer to keep the action smooth and stutter free. I have the basic 1.5 high speed...shouldn't that be enough? It doesn't happen all the time, just in certain applications. Are there any adjustments I can make to keep this from happening. Thanks for any ideas. IE-7 on a machine with Vista. 
Buffering??