My advice has always been, if you don't have the money for a sooper-dooper gaming computer, to have lots of fun with FSX, with many of the settings maxed for an amazing graphical experience ....
...then install FS 2004, and twiddle all the sliders around until you are running the Sim nice and SMOOTHLY, and you like what you see!
"SMOOTHLY" is the operative word!
You will be surprised just how good FS 2004 can become, with the careful settings!
...and most add-on scenery works fine with FS 2004, without frame rate drops. Lots of it around!....Just avoid installing complex airfields, (and LOCK the Frame Rate to 20FPS!).
There is a mountain of FREE stuff to improve the Autogen scenery effects; trees, ground, water, clouds, buildings, etc!...

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Don't write FS 2004 off, in your selection of Flight Sims!....

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Note that there are very few complaints or problems with FS 2004!
Without my present computer, (details listed below), I would still be running my copy of FS 2004!
Paul....FSX AND FS 2004....

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Win 8.1 64-bit. DX11. Advent Tower. Intel i7-3770 3.9 GHz 8-core. 8 GB System RAM. AMD Radeon HD 7700 1GB RAM. DVD ROM. 2 Terra Byte SATA Hard Drive. Philips 17" LCD Monitor. Saitek Cyborg X Fly-5 Joystick. ...and a Briggs and Stratton Petrol Lawn Mower.