So, how is FSX Runnning ?

It doesn't need any NVidia stuff at all if you don't have an NVidia graphics card.Al

What it does need however, is super-sample FSAA and the ability clamp negative LOD bias, which are required to stop the migraine-inducing flickering of autogen trees. Neither feature was available with my Radeon HD 4850, but I think AMD re-introduced SSAA with the 5800 series. So, quality should be much more similar between the cards now. AMD's drivers are still about 20% slower than Nvidia's in FSX however.FSX was running quite perfectly on my system, but of course as you start adding stuff, it slows down. To run it fully maxed out with some add-ons you probably need a 5+ GHz CPU.