Hi,
Especially when panning around in the VC or outside the aircraft, the remaining 5 cores of my CPU come to live and hit 100% for quite some time (especially after FTX Vector and Open Landclass EU, they will be at 100% even with no panning). I have cars and ships reduced to nothing, and very low traffic.
So, I would say that a dual core CPU and a gtx750 is not really enough with modern addons like the CS777 in FSX.

BR
Anders