In computers what actually connected for fast downloading in uttorent or ares except for connections?

ive been experiencing problem with my downloading now using ares and uttorent and i dont know why because before when im using my hp laptop computer and im downloading movies my download rate is 90kbps and up but now im using dell gx270 desk top my download rate is 20kbps down. i dont why does it happens i think is not the connections coz our connections is fast we are downloading 100kbps what is really related in computers for downloading i mean in hardware? sorry for my grammar hope youll get me thanks