I can't speak for 1111 as I only started playing DCS about a month ago, but I do have some FPS experiences to share about 1.2. I quickly became addicted to this game and have updated almost my entire system so I have a good before/after picture. My original specs:
GA-790XTA-UD4 Mobo
AMD x4 970BE @3.5GHz
Sapphire HD 6870 Xfire
8GB CL9 Ram @ 1333
PCPC 750W PSU
With this system on a 1920x1200 28" HannsG on LOW-MEDIUM settings and low AA I was getting sometimes down into single-digit FPS on ground/near cities and 20-40 in air. Lots of stuttering, playable but not too smooth. Choppy almost constantly. I then did some reading and through a couple different purchases got set up with this system just a couple of days ago:
Asus P8Z68-V/Gen3 Mobo
i5-2500K OC@ 4.5GHz
HIS IceQ HD 7950 OC
8GB CL9 Ram @ 1600 (same sticks)
PCPC 750W PSU
WOW what a difference. I now get, with max settings, 25-55fps on the ground and 40-75fps in the air on the same monitor. Buttery smooth. CPU doesn't ever break 50ºC and GPU doesn't break 53ºC. As it happened, I upgraded the GPU first and found by my own experience and reading about those of others with DCS that the CPU is typically what bottlenecks a system based on that DCS only uses one CPU core. I then upgraded mobo/CPU and got a much bigger fps jump than with just the GPU. Hope this helps!