I was wondering if I can load/unload ORBX easily? ie, fly with default, then fly with ORBX? Want to take some before-and-after screenies.

Thanks!

They have a configuration program used for, among other things, generally enabling or disabling it.

Heretic is right. It's called 'FTX Central' and orbx installs an icon for it on your desktop (see your FTX user guide).

Of course.

Ugh! Bit the bullet and bought ORBX PNW and a Carenado C208. I tried BOTH on Portland Intl airport and my FPS was in the single-digits! 7-13fps or so, it was painful to fly. Using the default C208 sitting on the active runway, I get 11-12fps, Carenado gives me 9-10fps. Reloading the default FSX scenery gave me 22-23fps with the default C208 and 18-20fps with the Carenado aircraft. ORBX eats up half of my FPS?! Help!

GPU is a HD 6970, FSX is running in windowed mode. Here's how my settings look:

Your FSX config is way off from the recommended Orbx settings since they add so much more autogen compared to default FSX.

Check in FSX Central or your <DIR>\FSX\ORBX for the Orbx PNW PDF manual and it has a section for what settings you should be using, right off bat I see some serious CPU hog settings on your screenshot (vehicle density and traffic, clouds at maximum etc) which I don't even use with my beefy rig since FSX is so bad at optimizing traffic AI code.

Try their suggested settings and then fly out of somewhere like their freeware KHQM airport instead of PDX which is right next to downtown and see if the framerate improves.

Yes, that User Guide has been brought to my attention. I've since followed the advice to the letter and with the default C208 I get 23-29fps, mostly 25-28fps sitting on the runway. Carenado's 208 gives me 19-24fps, mostly 21-23fps. Nice! It's playable now, but I wonder what else can I do to get even more FPS?

Then again, I guess flying out of "downtown" is a good idea of "stress testing," I assume I'll get better framerates once I go to the bush countries?

Is FSX still CPU-bound? Does it make use of more cores now or is single-core speed (higher GHz) still an important factor? Might need to re-OC my machine. Is my 6970 GPU lacking in any way?

Yeah FSX is very CPU bound but AMD video cards do not do well with it because partly the architecture and also AMD admitted they pay no attention to FSX in the drivers, whereas the architecture of Nvidia cards works better with FSX's non-standard graphic engine and they continue to tweak their drivers to allow for features that help (sparse grid supersampling and the recent adaptive vsync features really helped remove all stutters for me).

Still if you are getting ~25+ FPS steady then that is very acceptable for FSX, I used to run FSX with my old 5870 with similar performance locked at 27 FPS with supersampling on and it worked fine for me since you are not having to shoot enemies or anything.

I eventually moved on to a Nvidia card with FSX being one of the things that helped me decide in that direction, but I still lock my framerate at 30FPS even now so that it will stay steady even with all the detailed scenery and aircraft addons, I prefer a steady framerate to one that fluctuates up and down.

If you need in depth FSX hardware and driver tweaking info I can recommend the AVSIM hw/sw forum:
http://forum.avsim.net/forum/325-hardware-operating-systems-discussions/

Also I found fullscreen mode always has better framerate so you may want to try that as well if you are still using windowed mode.

Also the following FSX.CFG tweaking really helped my FSX performance when I was on AMD:
http://www.venetubo.com/fsx.html

See the pinned FSX tweak subject on this forum.

I saw that tool mentioned so many times and never tried it. Finally did and it bought me ~ 5 more FPS. That's the difference between 15 fps around KSEA or 20 fps around KSEA. HUGE! I was hesitant to pay money for ORBX until I realized I could have that extra boost.

To add to kludger and malibu43's excellent recommendations, this is how I've optimized FSX to run orbx PNW on my rig:

1. Focused on getting more GHZ from my cpu: OC'd to 3.5 (AMD Phenom II 'zosma').

2. Defragged my hard drive after every major addon installation.

3. Followed orbx's recommendations for the display settings.

4. Recently purchased a SSD dedicated to my games (FSX in particular). (Note: This negates the need for defragging and it's fast. Very fast. Get one.)

5. Picked up this little number for about seven bucks: FSPilotShop (to tame CPU hogs such as ASE (Active Sky Evolution)).

6. Got rid of my girlfriend. (Nothing slows down your FSX experience like the threat of withholding sex if you don't start spending more time with her than, and I quote, 'that stupid computer fly toy'.

All in all, I get pretty decent FPS (in the twenties) with very few stutters. I don't even bother de-activating PNW anymore.