Stuttering meters and transport clock

[bryanbassett]

My Meters and running transport clock are pausing for a split second every two seconds. The audio in not affected. Any ideas what could be causing this? I recently upgraded to 5.1 from 5.0 other than that no recent changes except for a Audio drive defrag.
Thanks

[bryanbassett]

Thanks Mr Seven,I must admit being up to the wall on resources.
I just recalled having this problem before in 5.0 so it's maybe not a version problem..I checked the rest of the mixes (I have several on this song) and all other session files run fine as do the other songs for this album with essentially the same amount of tracks and plugins. It seems to be some sort of file corruption. All i could do before is save as many settings as possible and transfer them to a new session. Alot of wasted worked in the edit window though. Has anyone experienced this problem or bug?
thanks
Bryan

[Mr_Seven]

Protools designates processing power to audio engine first. Video gets what's left over so to say. Most likley, your session is close to max and so the video stutters.