I'm posting this in hopes that someone else will avoid the agony of a two hour complete reinstall of FS9 and ALL of your add ons after you have experienced a sudden drop in Frame Rates.I have an Asus Intel 3.2 Ghz MB with GeForce FX 5900 video card which feeds two 19 inch analog monitors operating with nVidia's driver 66.93 Dx9.0c in DualView mode. I have my frame rates locked at 20 and run SquawkBox, FSNav, and AS2004 WX generator on the second right hand monitor with the cockpit and "windscreen"/scenery view windows on the left. Without warning, suddenly my FPS rate went down to around 10 from 20. Oddly, when I switched from windowed to "full screen" mode with Alt+Enter, the FPS went back up from 10 to 20. This was "smoking gun".Somehow, I had moved the cockpit/windscreen windows slightly to the right so just a tiny bit of the right side of those two windows were displayed on the right monitor. When the cockpit/windscreen windows were moved left so they did not appear on the right monitor, my FPS returned to 20! If just !!TWO!! pixels from the cockpit/windscreen windows are displayed on the right monitor in windowed mode, the FPS is cut in half.Moral to this aggravating story: Click the "Maximize" button in the cockpit/windscreen-scenery window before you give up and reinstall everything! Now that everything is back to normal, I'm going to go console myself an FSD Christmas present. {;-|Live and Learn,Larry

Hehe, I've been caught out with that one before too! Now I always keep a pixel or two buffer around screen borders to make sure it doesn't happen again.Gary

Yep... Been there - good post, hope it helps someone down the line.__Josh