i am going to asume you are on windows
if you look at all of the network traffic flowing through your connection you will see it is not what you are using
but it is how you are being used
if you have 2 movies loading to flashplayer in the back ground, and a MMORPG game playing, and try to run speedtest.net
your speeds will be poor
but those are the actual numbers the test achieved.
reboot. turn on the firewall, let NOTHING connect to the internet, load 1 browser and run a full ping diagnostic
your numbers will be amazingly better
the point is this
your PC is transmitting SO much data of you being a case study it is wasting your bandwidth like crazy. insane crazy extreme waste.
now after you get a handle on ONLY letting data transmit that you want to transmit (firewall) i'll point to the prerequisits
the first things to check are your connections, wire, OHMS, electromagnetic interference, over heating modems and routers, malware and virus cleaning, basic PC dynamic functional maintenance, and the list goes on
this should never be over whelming
this should be basic knowledge taught to all kindergarteners and practised every day by every person
so,,,there are a few things to think about,,,and i wont even start into the scary stuff