Before I installed FSX, I uninstalled the Demo2 and the Beta, then I defragmented the drives. After FSX installation, I took a small flight around Seattle, found that the frames are not like the Beta. I checked the drives and found lots of fragmentation after the installation. Defragged again and twice the drives, took a flight in Seattle, and the frames about doubled. I think someone mentioned this before in one of the threads.

I think Bill Leaming mentioned that FSX installs files quite randomly all over the drive. Thanks for reconfirming this. I'll do the same.