The connections are "capped" for more residential area customers, since its one big pipe per say a few blocks, each connection is limited upload so they can all have a reasonable upload speed, you can uncap your conection from the box but if they find you (while installing someone elses conection) youll probabaly be banned for a long while and since most companys only provide a certain region you wont be able to get cable and youll have to switch to DSL or viceversa.
Alternatly there are programs out there that uncap your conection through software, just do a quick google search and you should find some, again if your company finds you your screwed but if you need the speed go for it.