Thank you!
You're right, it should be more than enough, I'm surprised that it' struggling. It must be because I increased the physics accuracy in the December release. That will make it more demanding on the CPU, although I don't notice any real difference on my computer and it's certainly no supercomputer (It's a windows machine though, not sure if thats got anything to do with it).
In the December release I also introduced SSAO effect to the carpark level, but that shouldn't make a big difference.