I'm hesitant to try installing that driver in Win 8 after reading this page...
http://plugable.com/2012/12/01/windo...st-controllers
seems like the updated intel driver is for Win 7 and not Win 8, the "downgrade" is not straight forward to install, and results in loss of UASP (whatever that is)
BUT if it is reported to solve the Ethernet problems, I will give it a shot
(sorry I guess this post is not too helpful)