I know this doesn't make sense but with my QX6700 quad processor I get better performance in FSX with my Processor Scheduling set to background services. Everything is just smoother on my system.

Please explain that better..I find what i think you're saying very intresting...Thanks

It all started with my system running FSX somewhat slowly.. ie medium settings and flying around KIAD getting 9 to 20 FPS. Thiswith Traffic 2005 set at 40%, GEX, UTX with various planes stock and commercial. I also am OC'd at 3.2 GHz with 4G ram.I'm pretty sure I used to get 20 - 30 FPS flying the same or higher settings. So I tweaked and tweaked and just couldn't get what Ithought I should from my system.I dropped all settings to min and got 50 - 60 FPS as expected. I balanced everything out and to have what I consider minimum eye candy.At 5K no problems, but after dropping to 2500 major variances in FPS from 7 to 24 or so.. not all the time, but very noticeable.So on a lark I set my system process scheduing to Background Services and now the major variances are gone.. no big improvement inFPS, but a definate smoothing with much less variance in FPS.XP PRO SP3, Rclick My Computer select properties, advanced performance, advanced.

this is on which OS? And where did you configure the scheduling? Is this in the control panel under "System"?