Sudden Framerate drops on overpowered PC

[jens]

It is normal that the framerate drops to 30 from 60 if you have vsync active, if it can't keep up with 60, say only 59 fps, then the framerate will be 30. It is possible that if you manually edit the settings file in documents/amnesia/main/ and turn off LimitFPS that could change the behavior to slightly better.

Could also be that you are running the game with high ssao and samples? You should leave those at default as they are very demanding and makes extremely minor difference. With default the game should have no problem staying above 60.