when my former cable modem die several year ago , I replace it with the Zoom Technologies , Inc. model 5241 , and I have not experience a single problem with my Comcast internet connection since that time . download speed , as measure by the flash -lrb- Adobe -rrb- download\/upload speed test at the dslreport site , be typically 3.5 megabits\/second , but I have measure it as high as 6 megabits\/second . these number be probably determine more by Comcast than by the cable modem , but they do indicate that the modem perform at this speed at a minimum .