im running the game at 400*300 with an nvidia 8500gt smoothly over the sea

[bongodriver]

its optional put a lot of buildings or few, why none?

they probably didn't anticipate you, or anyone having a last century graphics card below minimum spec to try and run it.

I appreciate you are having fun too, but I'm not sure you can expect too much help on your setup because practically nobody will be trying to do the same.