I will answer some of the issues addressed as I have time.
Congo,.. full dual core processor support is found in Windows Vista which runs FSX a bit different. The game itself is currently not fully supporting dual core however there is a patch being developed for DX10 and a few other things.... and you know where thoses patches are aimed and why. We already had that discussion.
I fly FS9/FSX in WindowsXP x64 and Vista x64. The software runs much smoother for me in those titles.
Dual core support is in WindowsXP however 2 items must be in place... 1) Windows must be INSTALLED with the dual core processor in the system and the BIOS fully supporting the CPU. 2.) The latest AMD processor driver, AMD dual core optimizer AND the Microsoft dual core hotfix with registry edit must be applied in the correct order.
Once that is complete whenever you boot into a 3D application the system will automatically set affinity timing to a single core and balance any other useage so the core dedicated to the 3D application is allowed to have as much cycle time as possible.
Vista takes that to a whole different level.
Patches will be released next year for FSX and Vista.
Brett... I am not sure why you are having the problems you are seeing however based on the config settings I see I suspect hardware, windows settings/system files