My tip, to be on the safe side, would be to get Dad BOTH games, FS9 AND FSX...

...!
He won't be disappointed then...

...!
I have both Sims, but I am still enjoying FS 9 because my present system is capable of running it smoothly with everything wound up to the maximum...

...!
FS X, on the other hand, for me, is extremely sluggish, and with the scenery, Autogen and effects, etc, turned down, results in a much poorer visual game...

...!
Paul...(Owner of
all most of the MS Flight Simulators... 8-)...!
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.