I have a pretty shitty dual core pentium and I have no issues with FPS.
How shitty (GG2 runs on only one core IIRC and a single core of my Q6600@1.6 GHz might not comparable favourable with a single core of yours for instance)? Anyway my sister and I were both playing it on our respective computers and we had the same problem, so we quit playing cause it was so bad. It was never like this before, it felt like that time I played GG2 on a 10 year old machine.
And you released a new version without reverting whatever causes the FPS problem, it's kind of a missed opportunity.