[M4tt0]

Hi guys,

Sorry, only checking back now. I have been running the system most of the day and it is stable again. The ONLY change I applied was switching to 720p resolution like fritsch recommended last night. Anyways, here my former settings and hope this will still be helpful for you:
Settings -> Video -> Playback:
* Adj. display refresh rate to match video: off (had MASSIVE sync issues video to audio before. Could also not be overcome with the recommended advancedsettings.xml)
* Syn playback to display: off
Settings -> Video -> Accel.:
Just like recommended here (post #1) with
* Use VC-1 VAAPI: off
* Prefer VAAPI render method: on
Settings -> System -> Video Output:
* Monitor: Default (as fritsch noted I have an old HD-ready monitor that is giving me LOADS of trouble these days!)
* Resolution (then): 1920x1080p (my monitor ran on 1080i). One comment here: I tried the 720p mode earlier. I'm not 100% sure now but for one reason or another I was not able to use it on OE/Gotham. I believe it had to do with overscanning in Live-TV vs. rest-of-XBMC. It just did not work. With your test environment now it works flawlessly as far as I could test!)
* Refresh rate 25
If there is anything else of relevance, please just let me know...

Best,

M4tt0