I just installed a DC3217IYE with Windows 7 and all available updates, all the latest Intel drivers.
With the NIC link speed at autodetect (or set to 1Gbps), I get very bad pixelization viewing or recording TV in Windows Media Center. When I set the NIC to 100 Mbps, it works fine.
Replacing the NUC with my Latitude E6420 laptop (running at 1Gbps), it works fine.
Could be related to the issue discussed here: UNHAPPY - HD HomeRun Prime major issues with Intel DH67CF & DH67GD motherboard NICs