I have had comcast's 6mbit/768k cable service at 3 different residences and I always run into the same situation: I need to log in to some FTP servers 4 or 5 times to get my maximum bandwidth usage. For example if I download one file at a time my average speed is 150KB/s but if I download 6 files at one time my overal bandwidth is over 800KB/s. The FTP server is located in a Dallas, TX datacenter hosted by Layered Technologies. The FTP software is not doing any throttling or anything to slow things down this much. Other people depending on their location consistantly get 1Mb/s downloading 1 file at a time. I have used FTP servers located in Seattle, WA which is near where I live and I am able to get 700KB/s on one single download. I also have the same problem uploading to the FTP sites in Dallas, where one single upload at a time starts for the first few seconds at around 15KB/s (which is slower than it should be but acceptable if I can do multiplte files at a time), but then it drops down to 1.8KB/s for the remainder of the time.
I am using Linksys equipment (I had to upgrade once previously to get maximum speeds, before no matter now many files I downloaded at one time I would only get around 300-400KB/s). Cable ModemBEFCMU10 ver 3. Wireless G broadband Router WRK54G. I have one PC on my network full time and occationally turn on my laptop or Xbox but not when downloading.