Here some tweaks to improve framerate.

[JG5_emil]

Staggering improvement. This man deserves a medal!

I found that things actually got smoother the more I increased the level of detail. Everything is now set to high/very high with grass and roads on. I left shadows off as they flicker and reduce fps and also building amount is on low. Game rund like a dream except London which is playable but stutters a bit. Resolution is 1280x720

Fantastic!