I have Comcast and I pay for 120 Mbps. I have a Motorola Arris SB6190 and my router is a new AirPort Extreme. Now, I can't get a consistent connection of download speed. It always is up and down. Like this picture. My ideas how I can keep it constant and steady? I ask because there are people saying they get steady speeds with the SB6138 and the one I have has 32 channels compared to 16. Just so you know, all I did was connect it and got it activated and that was it. Didn't mess with any settings.