Hi McGherkin and oceandream
As mentioned before, the listed 3 GHz processor is a single-core P4 processor, which is quite an old model.
Since I've realised that, I'm not very afraid anymore. A modern multi core processor should beat this one.
Of course we had to reckon that all the things that we have asked for in the last months - better harbours, better water surface, bigger environments etc. - costs more calculating power - so it is only natural, that the requirements are higher than for SS08.
But this is a usual process in every software series.