loss of speed bec of router?

beginner q:

If I have a cable modem that it used for a desktop. then got a router to connect to a computer in another room, does the router slow down the connection on the desktop bec so of the signal is taken up by the router's signal?

thanks in advance...

Most of the routers out there communicate at many times the speed of your best internet connection. Only use that speed for file transfers between computers on the router... assuming they can also work at those speeds (network card, signal strength... etc etc etc).