Comcast be my isp . this cable modem be on Comcast 's approve list for all residential speed tier but be sure to check for yourself before order any modem . I have Performance internet tier and get about 21.5 mbp download and 3.8 mbp upload accord to speedtest.net . previously , I be get about 11 mbp download and 1.8 mbp upload use a old Motorola sb4100 . I have not have any problem with the modem overheating .