I had a similar problem with VLC player. Updated to newest version, problem gone.
I can't say for the DVI issue as I dont use it however I do have the DXVA 'macro blocking' problem when both re encoding video or playing back (XBMC ,MPC).
At present I feel the video playback has been overall a little unstable and disapointing in comparison to my little WDTV which is steady as a rock , maybe i just havent got it set up right?
CORE I5 2500
I also have the problem on a Core i5-2520M with the Intel graphics, but not when I´m using the nVidia card. So this has to be an intel problem and it is not fixed with the newest driver.
I also recall that this problem exist for over a year and is still not fixed!
Am also having the DXVA problem in VLC with the "GPU accel" box checked with my i5-2540m in a Thinkpad x220 (intel HD 3000 graphics). Interestingly though, DXVA works just fine thru MPC, Microsoft DTV-DVD codec. Hope this helps somewhat.
I have the NUC5i5RYK and the latest .4222 intel graphics driver.
With DXVA checked in Plex I'm seeing major Macro Blocking with VC-1 encoded video.
I See you created another thread. Please stay there since this is a very old thread and your product is a different platform: