[nIGhT-SoN]

Hello everybody!
I'm an xbmc user for about half year and I love it! I appreciate your work so much and now I need some help. Maybe someone knows what's the problem, but when I try to play .mov files the image it's not fluid while I move the mouse or while navigating through the menus. Outside of xbmc works fine, I've tried MPC-HC. I haven't changed anything like sync with the refresh rate or something like that.
I've tryied with DXVA enabled aslo with it disabled but the same thing.

What could be the problem?

Thank you in advance!

Running:
XBMC 12 default skin
CPU: Intel Core2Duo Q6600 @ 2.4Ghz
RAM: 2x1GB DDR2 800Mhz
VIDEO: Gainward GeForce 8600GT 256MB 128bit Bliss
AUDIO: E-MU 0404 USB 2.0
HDD: Seagate 500GB 7200RPM

[nIGhT-SoN]

Seems like it's not only with .mov files. I've found this problem in some .avi files too. I was watching Star Trek Enterprise Season 2 and when an episode is starting or when it changes to a new chapter from black to the image there is this laggy image, like a slideshow. After this fade in part, all works fine. I can't seem to find what is the problem.

PS: I don't have this problem with mkv files, HD, full HD and the problem is only in season 2, season 1 of Star Trek Enterprise worked fine also .avi files.