About overclocking, the main goal of any overclock attempt is stability, its not good enough with load Windows and jump into the desktop because your CPU can be unstable under a big load of process, it can go into Windows and run low demanding programs and then crash on the high demanding ones, that´s why the overclockers runs burning tests for hours, to reach a 100% stable overclock.
you seems to know about this so I'm not saying this to you but to the audience for everyone sake.
What is for sure is that the performance of your computer is strange, I have better results with my ancient and burned dual core and my cheaper ATI 5870, I had a quick fly over your places and this is what I got
First all this is my configuration at 1920x1200 :
* Note that AA is off because I´m using
SMAA :
http://forum.1cpublishing.eu/showthread.php?p=409386
It is enabled in his preset
SMAA_PRESET_CLOD_HIGH.
Screenshots :
But not all was well ...
The result is better than yours, it still low FPS but good enough for my hardware, and the only crash I had is the one in the picture.
I can have nice fights just avoiding London, over usual landscape 30-40 FPS at low altitude and without problems over the chanel (over 50 FPS).
Im happy with this performance, its good enough to have some clashes but I'm building a new rig, new board and quad-core CPU, and also looking for a 3GB videocard too
Hope you get your problems sorted, cheers ...