The issue is when two reflections see each other (one on the floor, one on ceiling) they reflect each other multiple times and it really slows things down when it's like 4 times. Idk why the default is that high. I know from other post that it's changeable but no one said where. google seems to hate showing the answer even though there's some old post (like same search term a week apart and what didn't give any useful answer now did. So here's the fix hope it helps someone. add a line to the map info of each file with reflections and