Video playback issues 11.3.1 and 10.10.3

I cannot playback video without it getting laggy and out of sync. I guess there is something new and different about the PT 11 video engine compared to PT10 and MT Lion where I never had problems. If I open the same session that plays fine in PT 10 and MT Lion and then boot under 10.10.3 and use PT 11my video plays back ok for a few seconds then falls out of sync and gets laggy while the audio is fine and there are no errors in PT. But in the Apple activity monitor I get Pro Tools Quicktime server (Not responding) and Quicktime_OPServer (Not Responding) The video is an H264 but I also exported it to Pro Res 422 and still it's laggy. I compressed it to lower than 1080p using handbreak to the original apple TV res and it was ok. I also notice
that quicktime 7 in general seems to be not playing the video back at full frame rate but Quicktime X has no issues.
Any thoughts?