I tried a little experiment

[senseispcc]

Hello,

It is a very expensive one also.
This was my system;
Windows7 x64 ultimate
12 GB memory 1333 MHz
Asus p6x58 motherboard
A fast 10.000 rpm hdd 300 GB.
GeForce 295 1,532Memory
Track IR 5
Saitek x52.

I tried every complexity mode and only low video setting did give a good but not great results, 20 to 30 fps average.

Then I changed my Graphic card for a GeForce gtx580 same memory.
I tried again all video settings and very high one did give me 40 to 50 fps average. One exception the flying over London at very low altitude, 10 to 20 Fps average.

For me the numbers of Buildings is a little problem.

I let you try to get to some conclusion.

Have a nice day.