To upgrade your Comcast modem, simply contact Comcast's online customer service to request a modem upgrade. A new upgrade costs a small fee per month, but allows users to access faster Internet speeds.

Comcast typically sends out notifications of modem upgrades. If you have not received a notification, simply request an upgrade on Comcast's customer service website. The upgrade provides a DOCSIS 3.0 modem that is powerful enough to handle the fastest speeds offered by Comcast for only a small additional fee per month.

In addition, you can purchase your own upgraded modem. Comcast recommends using its modems, since it offers quality service when its modems experience technical issues. In addition, Comcast provides a website to help ensure the modem you purchase is able to handle your Internet speeds. Simply visit, select the service and speed of Internet that you receive from Comcast, and wait for Comcast to bring up a list of modems capable of handling the maximum Internet speed for your current plan.

To take advantage of Comcast's special features, which include allowing you to upload and download large files quickly, be sure to purchase or lease a modem that is designated DOCSIS 1.1 or higher.