Solution to stuttering/pixelated TV

I wanted to post this information so that everyone can benefit.  My symptoms were Internet worked just fine going up to 14Mpbs which is normal for my house, however, sometimes the HD TV signal would stutter or pixelate.  It did not matter which TV I watched it on and it did not matter whether it was a recording or live TV.  I had a technician come out and he laid a new cable from the box outside into my house, but that did NOT solve the problem.  The DSL modem was connected to my home Cat 6 wired network and the DVR and other receivers where also connected to my home Cat 6 wired network.  For testing purposes, I moved my TV and my DVR right next to my DSL modem so that none of my Cat 6 wiring or house 24-port switch was being used and the problem went away!?  Therefore, I knew it was not AT&T's problem but something in my house connected to my network.  I moved the DVR and my TV back in the living room and started testing.  I pulled out all cables from my switch except the one going to the DSL modem and the one going to my DVR.  The problem again went away!  That proves it is not my switch nor my home made Cat 6 cables (I crimped the RJ45 connectors on myself).  I then started connecting 1 cable at a time into my switch until I found the one that caused the problem.  The cable that caused the problem was connected to my Macintosh Thunderbolt display.  I then knew it probably was a driver issue with the network card inside the Thunderbolt display.  I started changing the driver settings 1 at a time until I finally found the culprit!  It was "Flow Control".  By default, Apple chooses "Full Duplex, Flow Control".  I manually changed it to just "Full Duplex" and the problem is finally solved!!

I have no idea what "Flow Control" is, but if you read about it on Wikipedia, it does NOT sound like a good thing.  Long story short, Apple's implementation of Flow Control and AT&T's Uverse DSL modem do NOT play well together!!