Generally speaking I find Directory Opus runs pretty efficiently. However, every once in a while it will start using 100% of the computer’s CPU power. This causes the system to bog down severely. I’ve noticed that this behavior seems to be associated with opening folders (or multiple folders) which contain numerous video clips. I initially assumed that it was caused by the generating of thumbnails, but the problem occurs even after I set the default view mode to “details”.
Once it enters this state, it will continue to hog all the CPU power, even after I close the lister. It only stops when I manually terminate the dopus.exe thread.
There's some info on tracking this down in this FAQ, however it sounds like you've already got a good idea of what's causing it.
If you disable the Movie plugin the problem should go away but the underlying problem is probably caused by a video codec misbehaving, perhaps due to something particular in some of the video files. If you can track down which files cause the problem then you should be abel to work out which codec is causing the problem and disable/remove/update/replace or bug-report it.
By the way, plugins will still be called to extract information while in Details mode if you have the Description column turned on, or one of the other columns like Dimensions and so on.