So I just spent a little while tweaking FSK to run well on my system. There are a TON of guides out there for tweaking FSX but none of them seem up to date. Basically 90% of the info in them was not applicable to my machine. I thought I'd post what my setup is as it may help someone with a modern machine trying to set this thing up

My rig:

i7 950 overclocked to 4.0GHz
ATI HD5850 GPU
eyefinity running 5760x1080
Win 7 64bit
FSX Deluxe SP2

I attached my config. Here's the items that made big changes to my frame rates. Every setting affected it a little but these had MASSIVE impact on my frame rate. Unless otherwise stated my settings as those recommended in the online guides.

Settings - Display - Graphics
=============================
DX10 - Absolutely terrible. Graphics flicker, disappear at random and otherwise look terrible. 20fps penalty. It's off.
Light Bloom - Can't tell much of a visual difference but it cost 10+ fps. It's off.
Set anti-aliasing to bilinear and do not select the anti-aliasing box. Force AA in the driver. This gained me 7fps over checking it in-sim.

Settings - Display - Aircraft
=============================
This setting was interesting. I set all three exterior settings to "on" with no frame rate penalty at all. AND it looks great with the self-shadowing! Most online guides say to turn this off. I didn't need to.

Settings - Display - Scenery
============================
The "terrain and water" section was interesting. Basically I can max out all of these settings with zero fps penalty. So that's what I obviously do. Scenery Objects is where it gets interesting.

Ground scenery shadows doesn't affect frames but it looks terrible, flickering, artifacts etc.

Scenery Complexity. This was a BIG one for frame rates. Each click on the slider cost 10fps. Moving this slider made a huge difference. I settled on very dense as dense looked a little sparse for me and extremely dense didn't seem to add much. However, I can immediately boost my fps by 10 just by turning this down to dense.

Autogen density. Surprisingly this didn't seem to be too expensive at all. Maybe 2-3 fps difference per slider position. I set this to very dense also.

Settings - Display - Weather
============================
This was a weird one. Setting cloud detail to detailed instead of simple actually GAINED 5fps. Very strange but I'll take it!


Settings - Display - Traffic
============================
THIS IS THE BIG ONE

CARS. Turn OFF Those stupid little cars absolutely kill the sim. Kill it. As an example I could make my frame rate go from 75fps to 15 fps just by changing the number of cars displayed by 50%. Turn those little blighters off and you'll be glad you did.

Aircraft labels. Most guides talk about this causing problems but I have zero frame rate penalty using them.

Airport vehicle density. This is quite a hit on frame rates. I set to Low, Medium cost 10fps.

Airline Traffic Density. This really impacts frame rates but not as much as cars. I have Ultimate Traffic and can set this to 50% airline, 100% general and the frame rates are great. This gives LOADS of planes and not much impact on frames unless you are flying over a major airport when it can go down to 20fps.

FSX.CFG
=======
Couple of VERY interesting things here. #1 hyperthreading doesn't help with frame rates at all. I have hyperthreading turned off on my gaming rig. Turning it on did nothing for frame rates

AffinityMask. This was a big one! For a quad-core setting to 15 (1111) means "use all cores" and 14 (1110) means "use three cores" leaving one free. On my system setting this to 14 was a big improvement over 15. Way less stuttering and the sim ran much smoother. Leaving one core available is highly recommended instead of using all four.

TERRAIN_MAX_AUTOGEN_TREES_PER_CELL=800 This tweak limits the number of trees created on "dense" "very dense" etc. It raised by average frame rate by 7fps.

So remember, I'm NO expert on this just wanted to share my findings and what worked for me and what didn't on a modern machine running eyefinity. Hope this help someone new to get started.

My config: http://dl.dropbox.com/u/14465749/fsx.CFG

I just mentioned this in another thread but worth repeating.

I found this tool worked brilliantly
http://www.venetubo.com/fsx.html
but you have to follow the instructions exactly and there is a conf file that is not in the FSX folder which is the one that gets modified so you have to know where it is.

When used in conjunction with the frame limiter app it transformed FSX for me.

Yup, I did use that as my baseline setting. If you look at my fsx.cfg you'll see it was actually generated from that tool Thank you for the recommendation on that!

However, my frame rates went from about 15 (over atlanta downtown) using that tool to more than triple with the changes I listed here.

Adding this line in your terrain section should help a little as well, especially when using high autogen settings:

TERRAIN_MAX_AUTOGEN_TREES_PER_CELL=800

It basically limit the number of trees without limiting the number of building. Made a good difference on my setup as with Very Dense/Dense, there was way too many tress displayed.

This fixed my issue.

This also made a godd difference on my end: Do not use the in-game anti-aliasing/anisotropic filtering settings, use your drivers instead, and try bilinear/16 bit mode in FSX. This gave me another 5-6 fps without changing ANYTHING to the image quality.

May or may not work well on your end, but worth a try.

You'll also notice that the aircraft/region you fly in will greatly influence the framerate as well.
On my Phenom X4 4.0ghz, I get an ultra smooth experience when flying a simple Aerosoft BeaverX in the rockies... but things are a bit difference when flying the Superbug in the KSEA area with ORBX isntalled. Not a slideshow, still very flyable, but a bit more stuttering.


Cheers!

Nice one iam73!!!! That made a HUGE difference. Thank you. Both of these entries boosted my fps by 7 in my test area. I am updating my original post to include these. Thanks again!!!

I have not turned my cars off to be honest. Yes they do affect frames but I like the effect they give when flying at around 1-2,000 feet. I leave them and the boats at around 15-20% which gives a realistic effect without hitting frames.

On another point I have the weather slider set to maximum but always use the 'download real weather updates' and I find this gives amazing sky and cloud effects without any performance issues. I have no desire to install any third party weather as I am really pleased with the FSX version. I love watching the sky and clouds slowly change as I fly and the cloud/sky models are very realistic.

This can be cranked up allllllllll the way to 6000, if one wants.

FSX Defaults is 4500 and it puts wayyyy too many trees on the grounds as far as I'm concerned, so although 6000 works, it must transform rural areas into amazon-like forest

Thanks for the advice MacClean. Some good tips, but I have to disagree with you about DX10. Checking DX10 yields far superior results FOR ME. My frame rate is DOUBLED with DX10. Literally. Same graphics settings under both DX9 and DX10 yields superior graphics detail and clarity and frame rates TWICE as high. Everything looks and plays better with DX10. And I select trilinear and anti-aliasing in-game. Everything is beautiful and smooth at 19 x 12 x 32. It's not even close between DX9 and DX10. Also, I no longer have any runway flickering (the only place I had any flickering at all) since I installed REX2 and REX Overdrive. Those programs must've done something to eliminate it. I didn't expect it, but that's been the result. And REX2/Overdrive are amazing enhancements! DX10 is the only way to go.

I wonder if DX10 only works for NVidia cards? I have an ATI 5850.