here is something copied from one of the web pages when u google it:
Speed
Cable modems are generally faster than DSL. According to Cable-Modem.net, DSL provides download speeds of 10 megabytes per second, while cable modems can download up to 50 or 60 megabytes per second. However, as the Information Services and Technology Department at MIT notes, cable networks are broadcast oriented, which means your Internet connection is shared with neighbors and your connection may be slower during high traffic periods. Connection speeds on DSL may also be affected by certain conditions. According to Cable-Modem.net, DSL is a "distance-sensitive" technology, meaning that the further you are from your phone company's central location, the more your speed will suffer.
Security
Because a cable modem Internet connection is shared with neighbors, you must be extra vigilant in setting up security measures like firewalls and passwords. A DSL connection is very secure because it is a dedicated line used only by you