Very bad peformances inside the statue

[YouWillEatTheBugs]

Performances are mostly fine everywhere else, but my FPS drop significantly (up to 13-15) when I get inside the statue, which I can hardly explain given that there's not really much going on there, all while the nvidia bar shows around 50-60% GPU and 30-40% CPU usage. 

The game  also seems to lag more as the gameplay session gets longer ...my best guess would be that VRAM is not being cleared and visiting new areas gradually fills it up, but I'm not really an expert.