I have had the xfinity Performance plan and both the download and upload speeds are unstable. I tested the download speed by downloading large files from multiple websites (not P2P sites) and the speed changes every second from 300Kbps to maximum 3Mbps (same thing can be said about upload speeds, ranging from 90Kbps to 600Kbps). I have a Motorola MB7220 modem connected to a Belkin N150 wireless router. Could you please help me becasue this is becoming very frustating? Even video chats are very poor quality.