I also noticed a drop of anywhere from 8-25 FPS with same settings vs 11.25. I mainly fly the Zibo 737.
Furthermore, my XP is crashing a LOT. I have the processor clocked to about 5.0 (i7 9700k - 8 core) and the card slightly OC too (GT 1080).
Card reads at close to 6.9GB loaded into it at any one time with some headroom left, but it is clear to me the whole system is struggling. It is an Alienware Auro R8, 3 weeks old, bought specifically for simming.
I used to have all sliders at max apart from AA (one below top) and reflections etc turned off. Now I have to run all sliders one off max - this will see around 35-45 FPS with some clouds etc. All on a 1080p single monitor.
Laminar have pushed the envalope too far in my opinion. The 11.30R1 is not stable and is a hog on even strong systems. I hate to think what it would be like at 4k or if I decided to multi monitor. Very disappointing.