I have a flickering problem as well, for me it is very noticeable and annoying when watching TV content via Windows Media Center (Windows 7 Pro 64-bit) and the flickering generally happens when there is a greater amount of lighter colors on the screen.
Problem happens with the Intel HD 5000 video card on the NUC D54250WYKH.
With latest bios and drivers, so don't give me the standard "update drivers" line, please. :-)
The problem DOES NOT happen with the Intel HD 3000 in the Lenovo Q190!!!
I attached the Lenovo Q190 to the same TV with the same HDMI cable, same Win7 Media Center configuration and TV content DOES NOT flicker like the NUC.