Righto, here is the results of my experimentation:
Release version on gaming beast (AMD Nano + skylake i5):
Start up and hit rocket, completely empty map, defaults settings: 220 FPS, Bloom slider 0: >300 FPS. (actually hovering around 400 mark)
Load The Big Escape level, hit rocket, press E: 67 FPS Metrics panel 'shaders' indicator @ 37.
Move forward until point where first audio triggers (lots of shadow at this point): 75 FPS Metrics panel 'controls' indicator not even registering.
Reload Beta
Start up and hit rocket same as before: 140 FPS! Bloom slider 0: > 300 FPS same as before
Load The Big Escape level, hit rocket, press E: 65 FPS Metrics panel 'shaders; @35 (pretty much same as before)
Move forward to first audio point: 35 FPS!! Metrics 'controls' indicator @ 40
( please do not use profanity even abbreviated )
On my POS laptop (ASUS something-or-other with Intel integrated GFX):
Pre-Beta on TBE level : 12 FPS (all sliders minimised 29 FPS)
Beta on TBE level : 8 FPS (all sliders minimised 29 FPS)
So Houston we have a problem. I don't think it is the shaders alone and I doubt it has anything to do with Lua as in all cases the Metrics for AI was the same for pre-beta and beta tests.
Hopefully the above might help Lee track down what is going on, might be helpful if someone who isn't having any reduction in FPS could chime in, maybe identify whether this is related to a particular OS or GFX chipset? (I'm running Windows 10 btw), any Nvidia chipset owners like to chime in with their figures doing the above tests?
Been there, done that, got all the T-Shirts!