I am running FSX on a Q6600, 2gig DDR800 RAM, 512MB Geforce 8800GT machine i just built and i have overclocked it to 3ghz (from 2.4ghz). I am getting anywhere from 13fps to 80fps with most things maxed out (traffic 50%, terrain resolution 1m, mesh 70%, no bloom or DX10 enabled).On my AISuite program (came with my ASUS motherboard) it shows the utlilisation rate of my 4 cores. I took the snap below while playing FS. All other programs i.e. anti virus etc. had been disabled. Looks to me like FSX uses the cores just fine.

It uses all the cores, but the extras after the first are only used for one task (loading textures). This makes an important difference, but it's a long way short of making the best possible use of a multi-core environment.Tim

Enable the "show kernel times" option of Task Manager and be scared how much time is lost in the kernel. For me it's 60-75% that is just spent in kernel overhead on the other processor cores.I seriously wonder what this is about. Busy loops in spinlocks maybe? Doh. A serious waste of electricity.