I already owned FSX, since it came out. I already have about $2k invested in to it with PMDG and other high tech add-ons and hardware including yoke and pedals and joystick and throttle. So for $5 I figured I would check this out if only to see what FSX looks and acts like in a virgin state. I have 78 gig of add-ons in my original FSX.
I fired it up and the first thing it does is build a scenery database. Then it does it's auto config thing for you. It set up my graphics details to ULTRA on everything! A little bit shocking to me. So I left them alone and got into a small plane and took off. My FPS was set at unlimited and I was bouncing around between 55 and 85 FPS. I have never had FPS that high before, but my 50 some gig of scenery and meshes and REX and weather are not installed.
None of my configs for joystick or yoke worked correctly. It had my fuel mixture lever as my rudder control. I had it in the back position and started spinning in a circle! Saw the rudder completely turned out in an external view. So I have that task ahead of me. I hate reconfiguring input devices...
The scenery looked good, flying was seamless, no stutters or lags, just smooth flying.
I am going to see if I can add the scenery to it from the other FSX install. I believe that will work since I already reference scenery packs on several drives. I own all the Mega Sceneries from PC Aviator and a slew of airports. FS Genesis meshes are going to go in soon too.
All in all it appears to be the same. It runs great in virgin state, we shall see what happens as I bloat it up.