Try to properly configure, a router should not slow down your Internet connection. Whether you are using Wi-Fi or a LAN connection, your router is planned to allow a greater number of connections to your Internet. If the router is set up right, the Internet connection should pass through it to your system without any slowdown in speed.

On the Other: Configure the Router Properly
Besides allowing various computers to connect to the Internet, nearly all routers are equipped with many other features and options that offer a great deal of control over how your Internet is delivered to connected computers.

Bottom Line
Discuss with your router's owner's manual carefully when setting up the device. Changing any of the settings on your router without knowing very well the effect that the settings will have could result in a slowdown in your Internet connection. The greatest approach to avoid problems is to just connect your router with its factory settings whole.