I wouldn't think so, but realise that you may feel this way! Have you made any changes at all to your setup, new programs, updates or any changes to the modem settings or even the way it's actually connected. [New cable] or anything you can think of.
If you can post back with any information that may help, even if you think it's not directly connected with the modem. Someone just might be able to pick up on what is causing the drop in speed. j.