Plasma Panasonic GT50 having a hard time displaying what the NAS is Feeding?! (help)

So my TV seems to hate my computer, whenever I put a movie (it only seems to be movie because youtube and games seems to be flawless)
Games run really well and I don't have any trouble:

Software used:

VLC or XBMC

Hardware:

i5-2500k
GTX580 3 gigs
16 gig ram
Connected via a HDMI 60 foot cable
http://www.monoprice.com/products/p...=10240&cs_id=1025501&p_id=9173&seq=1&format=2

Trouble:

Any Movie downloaded (720p or 1080 we are talking about 4 to 6 gigs files) the image seems to shutter in a really subtle way. Like if the refresh rate wasnt able to follow what the media wants to push, imagine is pristine its really the mouvement that seems to ''lag'', it doesnt do that when I'm on lets say Twitch TV or on youtube or even in a game.

I tried with VLC and with XBMC and yet the trouble stays, I cant find it ...

Juste comme ca.. Moi jai une plasma Samsung.. pas la même marque.. mais je plug directement mon HD avec mes films 1080 p et 720p sur la télé.. et le software de la télé .. va très bien lire mes films.. as tu essayé?? au lieu de passer par ton ordi.. Je sais pas par contre si ta télé à cette facon de faire..

finalement XBMC passait par VCL pour le codec et c VCL qui laggait ... hey bin