In short, FSX is a true performance hog, so the rule of thumb is "the better (faster) hardware you have, the better it will run".
But!
The best hardware won't get you the most satisfying results if the operating system is chocking on junk and falsely configured drivers.

This is why I've decided to share this collection of very helpful tips with you. All of them are from Nick Needham, a kind of guru when it comes to understanding the way FSX works. I am a tweaking guy myself, especially ever since FSX arrived on my hard disk. I've tried many, many tweaks before, but none worked as well as Nick's.



Preparations:

• If you want, re-install FSX and Acceleration or SP2 (I recommend it). Here's how to do it properly:
  
• FSX Acceleration: (Ignore everything below the fat, underlined text for now)
  -> http://www.simviation.com/cgi-bin/yabb2/YaBB.pl?num=1197380641/1#1 <-
• FSX SP2:
  -> http://www.simviation.com/cgi-bin/yabb2/YaBB.pl?num=1197380641/6#6 <-
• Update your hardware drivers. Here's a guide how to deal with the video card driver and how to set it up for FSX (Note: Ignore the links to the 169.04 driver. It's hopelessly outdated.):
  -> http://www.simviation.com/cgi-bin/yabb2/YaBB.pl?num=1163028653/165#171 <-

Now for the real deal:

1) Windows tweaking

Read the posts by NickN carefully (print them out if you need to) and do exactly what he suggests. Don't worry if you don't have a "Prefetch" folder in your Windows XP directory. I've encountered that problem with XP SP3RC2 and I'll post a fix below.
-> http://www.simviation.com/cgi-bin/yabb2/YaBB.pl?num=1208959973 <-



2) Tweaking FSX on the FSX.cfg level

Values to play around with are listed here (Note: For "AffinityMask=" use either "1 = 1 core 3 = 2 cores 7 = 3 cores 15 = 4 cores", depending on the number of cores your CPU has):
-> http://www.simviation.com/cgi-bin/yabb2/YaBB.pl?num=1197380641/1#1 <-
(Scroll down until you reach "Here is a list of the ONLY areas one may wish to work with")


And that's basically all for the basic tweaking. Now for some special things...

• If you have XP 32 or Vista 32 and more than 2GB of Ram:
  http://www.simviation.com/cgi-bin/yabb2/YaBB.pl?num=1208959973/#3
• If you don't have the "Prefetch" folder in your Windows directory:
  http://www.besttechie.net/kb/entry/6/
  (Note: I recommend doing this after having defragged)
• A few further notes about FSX:
  http://www.simviation.com/cgi-bin/yabb2/YaBB.pl?num=1197380641/2#2
• In the FSX.cfg, change the LOD_RADIUS= setting in the [TERRAIN] section to 5.5, 6.5, 7.5 or 8.5
  This makes the "ring" around your aircraft larger in which the highest resolution ground textures are displayed, but comes with a performance hit (don't go any further than 8.5!).
• C++ Library update (the C++ library is required by FSX):
• 32 bit: http://www.microsoft.com/downloads/detai...&displaylang=en
• 64 bit: http://www.microsoft.com/downloads/detai...&displaylang=en
• Graphics card settings (mostly for NVidia cards):
  -> http://www.simviation.com/cgi-bin/yabb2/YaBB.pl?num=1208959973/#5 <-

Okay, so you're done now. What's left to say?

Keep your eyes off the frakking frame rate counter!

FSX is all about smoothness!

You have your FSX running perfectly if it is a smooth as possible at the best graphics possible for your system!
Finding that "sweet spot" (or G-Spot ) is a thing that can take a while. Feel free to adjust the sliders in FSX as well as some of the values in the fsx.cfg until you reach the perfect compromise between looks and smoothness.

A word on those "resized performace textures":
Don't use them. They are against the "maximum looks with maximum performance" philosophy.
Low-end systems (and some mid-ends) may be the exception.

Also, feel free to browse around in the threads I've linked to. They might contain more information that could prove useful to you.


Thanks for paying attention, happy flights and again thanks to NickN for his time to write all those things down.

If you have questions concerning tweaking FSX, post them here.

Stickied...

Thanks, Rick!

Just fixed the links in the initial post.