How about Microsoft Flight Simulator X, using all features of an Nvidia GTX 670 card which are supported by the game?
Just my opinion, YMMV, but FSX and the new P3D smoke everything else out there. I own Xplane, and it’s so not what they say it is, the scenery is basic at best, the uber-real aerodynamics don’t fly like what I know. You’re just going to have to have a dedicated gaming rig running W7, and play with Linux on some other computer. Like I say, that’s just my opinion, but you may like Xplane. If so, you can use linux for that. I don’t know about the GPU, but linux is pretty good at keeping up with drivers for the cards out there.
I love Linux, but it’s gotten too cumbersome to try to keep up with all the dual boots and other installations in my house, so I gave it up. I don’t have the time any more. I keep a few disks about, as they come in handy sometimes. My neighbor’s HD died and I booted her computer with a live CD and gave her strict instructions not to turn it off until her replacement drive arrived. Just so I wouldn’t have to come over and set up the printer again, otherwise she could have shut it off. She got along fine with it.