Hi Allan,
Details follow
What is the NUC model?
D34010WYK
Operating System version? if 32 or 64 bit.
Windows 7 x64 Ultimate
Video driver version?
10.18.10.3345
Also, the graphics report generated within graphics properties
Report in attached file
XBMC version 12.3
Symptoms are macroblocking on all .mkv files encoded with VC1 when using dxva2, it appears that this is a well known issue over on the xbmc.org forums as well.
http://forum.xbmc.org/showthread.php?tid=178421
Regards Phil