So, I built a new system last spring and finished it out with a new monitor and AMD XFX 6900 XT graphics card a couple of months ago...
I moved my Rise of Flight install over from my old PC, and got it all set back up with the proper options. I was appalled at the performance I was getting, like 25-60 fps flying around on the Western Front map, and 20-30 fps on the channel map. I did not remember such bad performance with my Eyefinity setup on my old Win 7 machine and started doing research. As it turns out, my old card was an AMD 295x2 (runs 2 GPUs on the same board) - and I had the "Multi-GPU" option ticked for that setup in Rise of Flight. On my new setup, I had not ticked that box because the 6900 XT is not a multi-gpu card. In reading the ROF forums it was recommended to tick that option, even if you do not run a Crossfire/SLI setup... Lo-and-behold I have my FPS back!