Your broadband service is a single speed to your house.
If you are getting different speeds around the house then this is due to the equipment you are using (possibly settings) and the technologies you are using to transfer data (Cable, WiFi, Electricity Over Power, etc.)
We can possibly give some ideas. Tell us a bit about your situation.
1) What is the layout of your home
2) What devices are you using (PC? Tablet?)
3) Are you using wifi? Where is the modem located in the house? What model modem do you have?
4) What is the difference between fast and slow speeds in your home?