@Asmodian:
This issue happens even in windowed mode.
And, well, you are right, it's just my issue, I may not even really need madVR, I may be all happy with e.g. EVR, often watching videos in windowed mode only. I don't want to make it sour for all other users. Sorry all.
... I just wondered if a separate thread for users with "luxury hardware" may have been useful. Not anymore, too late for splitting.