+ my computer is powerful enough to handle such framerates easily. Heck, I can even even run it with "veryfast" preset and still have a lot of CPU headroom. I actually get a less desynchronization if I run it with "veryfast" preset along with using a bit more compression on-the-fly.
Yes, I know, that makes no sense.
I would really like to figure out what exactly goes wrong. As I not only want to properly record videos, but it also "activated my curiosity". Weird things are interesting