I just purchased the router less than a weeks ago and have called Tech Support twice already.  Its a DIR-825 rev B. and 2.02NA firmware.  My connection seems to slow down from 16mb/s to about 400kb/s after a day or so.  Tech support had me change my NTU from 1500 to 1250 the first time and 1250 to 1492 the second time.  I have 2 wired computers and 2 wireless in my network.  All of my computers also have firewalls which someone told me could be a problem since my router has one too.  I have a Motorola 5101 modem.  Someone please help.