Please see the most recent updates in the "Where did the .com name go?" thread. Posts number 16 and 17.
This guide is more updated and I prefer it:
http://kostasfsworld.wordpress.com/fsx-software-and-hardware-guide/
Honestly, before you try any guide, all I would do is add the highmemfix=1 under the GRAPHICS section of your cfg and adjust video settings to how you want in inspector (or AMD catalyst). Nick N still has decent recommended settings for inspector (nvidia).
You know about Bojote's FSX tweaks ?...
Certainly THE ultimate performance boost for MY FSX!
http://www.venetubo.com/fsx.html
