The video not finished encoding issue occurs even with over-clocking turned off. When over-clocking is enabled, it almost always blue screens. I am running an Intel Core i7-4790k 4.0ghz CPU. When it is overlocked, it is running at 4.6ghz. I think a 'priority' option would be ideal in the renderer where the user could say 100%, 90%, 80%, etc. You could do a slider, do it 10% at a time, whatever you like. This way users could lower the load for prevent BSD (for me, for example, I would probably set it to 90%) or someone may set it lower like to 50% if they need to work, but want to get a render done, etc.
In any case, the corrupted video problem seems to never happen on the first render, but seems to happen very often on renders after the first render. Also, if it's helpful, I am triggering the start/stop of recording in the animation with triggers. I do 'freeze' things on load so that it doesn't attempt to start until everything is done loading and ready to go. Hopefully that helps!