No matter what value I set the slider to,
people downloading from me only get 15KB/s

If there's only one person downloading, he gets 15
as soon as a second comes on it splits it to 6/7 each
and no matter how many are on they all split 15KB/s
no matter how I configure my settings

I have a broadband connection and when I go to Network connections and double click it, it tells me the speed is 12mbps

Any Ideas anybody?