Swimming Video in PT LE 7.3.1

[japple]

Hi I'm using PT LE 7.3.1 with DV Toolkit2. When I'm editing I have the feeling that the sync. of my Quicktime MJPEG Video is swimming in Sync.!
It's not wrong spotted. Clicking in the Session has the same Frame in the Timeline, like in the QT Movie. When I hit play I have the feeling, that the Video is out of Sync.!
I'm using Mac OS 10.4 with Miro DC30+ and the Driver from Squared 5 on a Dual G4 1,25Ghz with 2GB Ram.
Has anyone else experienced this???
The Setup worked fine before with OS X 10.3, DC30+ and a Mix Core with PT TDM 6.4.1.

[japple]

I specified it a little bit. My Session starts normal in Sync. (pic.&audio) and after working some time it will get out of Sync.! After quitting Pro Tools LE and reloading, everything is fine. What is going on? Is the Videoengine in PT LE buggy? My CPU shows just a quarter load, so it doesn't seem to be my Mac Power! Digi?!?