At my local best buy that's what I was told when I was checking out new cable modems and got swarmed by the workers. Those speed's are dead on from what I was told, so who knows I'll believe it when I do some speed test's
Make sure you buy a D3 modem. I have a Motorola 6120 but you'll have to get the 6121 because the 6120 is discontinued. I frequently shop at the Best Buy at Holyoke Mall and they're always sold out of the 6121 modems. They always have a boatload of 5101 modems in stock but I have a gut feeling that Comcast is soon going to declare all D2 modems to be end of life soon (which means they'll no longer support them). My 6120 works good for me though although I have thoughts of getting the 6121 but the folks in the Comcast HSI forum on this site said that the 6120 and the 6121 are basically the same thing except for a few minor tweaks.