Doom's first level performs poorly. -- A Public Service Announcement.

I had someone ask how the first part of the game plays for me, after watching a video I showed from a later area. I recorded the first 35 minutes of play, and it's become clear that the first level performs poorly. Not sure why, but it does. The game starts with what I consider to be the "best settings" for beauty and performance. At the 28:07 mark, I switch to max settings. (by the way, my "best settings" are two clicks away from the max settings, when using a 390). i7 4790. 16GB RAM. Asus Strix R9 390 8 GB.