Well, I'm becoming convinced that the crux of the matter is in the ATV3 itself, purchased in Nov/2012. I found the software to be "up to date." I repositioned it around quite a bit, more than just a few inches, and the actual performance of the ATV remained the same. All three cables were checked, unplugged and re-plugged. I am unable to even view the Previews in a normal manner. Unlike before, when clicking on a movie to preview it now enters the "Accessing the Store" for a minute or two and that for a preview lasting only 1 minute and six seconds. When it finally appears, whereas before it would open there and then, it now shows a white coloured progress bar that hardly moves at all,( similar to the downloading a rental movie I experienced, but will never open even if you should wait until it completes its progress which takes an inordinate amount of time. It is most unlikely that I would care to venture renting a movie again under these circumstances. Incidentally, I have now been using the new Airport Extreme 802.11/ac for ten days now, but it should be remembered that no such adverse circumstances prevailed during the operation of the two prior ATVs nor this one until recently.