Nothing wrong with WOAI especially considering its price. Suggest you give it a try. If you're not happy, you can always switch to something else.
Lefu - Maybe the reason your old games ran better on an old sytem is because (A) those games were written for single core and/or (B) the clock speed of your old single-core CPU may have been fairly high.
As for FSX, when Microsoft was developing FSX, their thinking was that processors in the near future would be running at ever higher clock speeds. Instead, CPU development went towards more cores at slower speeds leaving Microsoft with a product release (ie FSX) that wasn't written to efficiently run multiple programming threads on a multi-core CPU. Subsequent service packs improved on this somewhat but FSX is still not very good at using mutiple cores. As for using a six-core CPU to run FSX, having all those cores available is in no way detrimental to the running of FSX. My thinking, though, is that using a six-core CPU for FSX is certainly getting into the area of "over-kill" given FSX does so poorly at utilizing multiple cores and given that an over-clocked 2500K quad-core runs FSX just as well as something like a six-core i9 while costing far, far less.