I have read here and elsewhere that running a projector in a non-native mode will slow it down because of interpolation.

I was running my Optoma EX525ST projector in a rearward projection mode with the screen about 24-30 inches from my eyes. I did this to see if I could get the virtual cockpits to show in real life size. However, I ran into a problem with reading the numbers on gauges. They were blurry.

I forced the projector to run in a 1280 X 1024 mode and found that I could see much more detail on the gauges. The surprise was that I didn't loose any FPS.

I think that with FSX being so CPU extensive the projector and GPU are just lopping along waiting for the CPU to feed them info. In other words the CPU is the critical item in the flow.

With the addition of an Artic Cooler, I have just overclocked my Q9550 from 2.8 Ghz to 3.4 GHz. I found this to make an amazing difference in FPS. I run locked at 30 FPS. With the stock 2,8 GHz I was running anywhere from 8-9 in high traffric with a known FPS grapper aircraft, to the 30FPS. Now, it rarely drops below 20 FPS. I can easily live with 20 FPS.