Could you tell me which field you were at in the Beta where you were seeing the FPS on your box running around 100+ FPS?
Pudgie, if you go to A5 to the SE of the starting base in offline, this is what I've been using, it's a grass strip single runway base.
With the latest beta client, 1080p resolution, everything maxed with FOV at 106, I'm seeing 125 to 144 (max) once airborne in the area around the drones. If I click reflections/environment back to 1, where I play in the MA now in AH, it's pretty much solid 144/max no matter what altitude I'm at. I've been trying it with shadows off, as sometimes when in fights I find them distracting, and the FPS meter doesn't move off 144 with them off, and environment at 1 or 2, and at max, just the odd dip into the 120/130s on the deck.
At 1440p, I'm not seeing a whole lot of decrease in numbers FPS wise, while idling on the deck, all settings maxed, it's around 95 or so @A5 base, and once airborne, is averaging around 130 I would say, sometimes it'll max out at 144, usually around 120 to 130, which is great since anything over 90 to 100 is really hard to distinguish. I just prefer 1080p as the targets are easier to hit in game. Hitting F3 while in the tower at A5, you get a great few of the trees up close, they look really good.
The more I'm messing around with it, the faster/better it's looking, I'm very interested to see what furballs are going to be like around say a couple of CVs.