FSX can't use dual cores/ultiple cpus/multiple threads because fs2000 cannot. Simple. Same engine, same limitations. So aces is correct in this regard. When they made fs2000, they never expected dual cores+ to be the norm. At the time, only high end servers used multiple cpus and those were cost prohibitive to the average user. For me, FS9/10 runs the same limited to 1 CPU or left alone across the 2.

I took Ed's use of the word 'crippling' as probably what he meant---that it reduces XP's efficiency with a H.T.-enabled CPU, if the user chooses not to use that enhanced feature over using XP with a non-H.T. featured CPU.That is what I also subscribe to.Not 'cripple' as in to render a real detrimental performance blow.Right Ed? :)Mitch

Correct.As for 16bit... can't remember the last time I ran something so... um... DOS. ;)