I have a Motorola Surfboard, model SB5100 cable modem. I have Charter for an ISP. I just got a email from them telling me my cable modem was outdated for their service and they suggested that I rent one from them. Is this merely an effort by them of trying to rent modems or have they changed something so that I really should have a new modem? My present down speeds are in the 15,000-25,000 kbps range and up about 1,000.