It was exactly the same for me. I had better performance then now, on the last box, before the upgrade.
My screen refresh rate is 60Hz and with the Vsinc on, before the drastic graphics changes, I was sitting at around 54-57FPS average after two hours of heavy online playing. Now I'm getting less then 20 FPS offline , with few plane flying and medium clouds.
Last year, I used to test heavy weather in FMB, with huge triple layers of clouds and it ran better.
I think they totaly lost their bearing with this game.
And I really loved it when it came out.
Everything looked so beautiful.