In my HT (one floor down) I have an Airport Express connected to a 1000GB switch then to an HTPC, Samsung BD player (with Apps) and an Apple TV. Also have Comcast 50Mb/10Mb service. Was watching a VUDU (HDX) movie last night (on my BD player) and it keep stoping. Ran speed test on my HTPC (both connected to the Express) and got <1.5Mbps down but >10Mbps up. Rebooted Express and same so I thought it was defective. Disconnected my BD and enabled it’s WiFi but move still keep stoping. Then tried Apple TV on it’s WiFi and it would also stutter/stop. However when I did a speed test with my iPad or iPhone in the same location I would always get up to 50/10 (even with the ATV stuttering). I rebooted my Extreme ac and the speed returned to all these devices (50Mbps/10Mbps to my HTPC via the Express). Now less than 24 hours later it is doing the same. My iPhone and iPad (and an iMac WiFi connected) continue to always work at high speed but my Express (I have another Express that just streams music so not sure if it’s effected), BD and ATV suffer from sporadic extremely slow download speeds while maintaining the full 10Mbps up load speeds. If I reboot the Extreme ac they all return to normal speeds. Could this be some type of antenna steering issue?