Help with audio & video playback issues, TV display type recognition & compatibility, HDCP messages, troubleshooting playback errors, advertisements, and resolving power issues.
This is what I did to solve the problem.
Possible culprit: degradation of compound between cpu and metal lid
Possible culprit: degregation of power regulation to network ic due to prolonged heat exposure, causing network instability over time.
Attempted first solution: clean black compound with isopropyl alcohol on arm ic and top of lid dip that contacts it. Take 15mmx15mmx0.8mm copper plate, get arctic silver on both sides. Put between cpu and plate contact.
Result: lost stability sooner. Heat is probably going around to network section of board faster. Thermal compound meant to balance heat load between board and lid?
Attempted second solution: keep first solution in place and... 
I found that adding small heatsinks to my 3900x reduced the operating temp to about 125F at 78F room temp.
