Poor netflix performance on uverse

I'm looking for help trouble shooting poor streaming performance of Netflix and Youtube on my AppleTV over uverse. The AppleTV is connected by wifit to my RG, everything has a fresh reboot, and the speedtest app on the AppleTV reports something on the order of 20mbps or so download speeds. That should be plenty for HD, non-buffering playback. But it is not. For both services, I often will encounter the playback toggling back and forth between lower and higher quality playback. Netflix, in particular, will stall. This happens both in the evening and the morning. There doesn't appear to be any issues with my network (strong wifi, no stale settings on anything), so I can only assume the issue has to do with uverse interconnecting with YouTube and Netflix. I'm not sure if this is related, but I have also noticed occasional stalls when doing a google search from one of my devices (ipad, desktop computer). I have heard that ISP DNS often has poor performance, so maybe this plays into things?

At any rate, I assume that if ATT sells a connection speed to my house that they make every effort to support that speed on the other end to various services that I would attempt to connect to. Given that 5 mbps is required for HD quality streaming from netflix which is way below my connection speed, any issues look to be on the ATT side. Any suggestions?