I have an Intel CPU but an AMD graphics card (390x).
All I can say is it really is worth it. The difference is staggering. It clears up all the jaggy lines, shimmering. Basically makes the game look like a modern title. And it costs you nothing to do because with using the in game AA settings your graphics card is basically doing nothing in FSX. the CPU does all the work. So not only does using nvidia Inspector / raedon settings make the game look much much better. It actually slightly lightens the load on your CPU. The raedon settings work fine for me now. What card do you have and I will try and help you get it working because it really makes a big difference. I had to make sure I was using drivers 15.12 then it worked fine. FSX.exe is set to run as administrator if that makes a difference I don't know but maybe.