Hi i'm only new here too and I recently bought a new computer so am quite new to all the 'techno' stuff. My specs are.....
Intel i5 3570K @ Stock 3.4GHz
8GB DDR3 RAM
Nvidia GTX660
At first when I ran FSX I was pretty shocked at how poor my performance was! I mean I was getting hight fps in some areas but anything with the slight bit of detail I would drop below 20 which I didn't really want after spending money on a new system. However I researched "FSX tweaks" and theres a mountain of information on the internet. One of the best tweaks I came across was using an external frame rate limiter to set your frames to 30fps. Also I downloaded 'Nvidia inspector' for my graphics card and was able to change a setting called v-sync to 1/2 refresh rate. This makes the game run so much more smoothly. Also I think theres someone on the web called "ventubo" or something along those lines that will actually tweak your fsx.cfg file for you instantly which helped a great deal.
Also as your card is a differnt brand you will need to find some software that is able to make changes to your grapics card. Have you got any monitoring software so you can see your GPU usage and temps?
What card has your friend got? Your processor is more than good enough to run the game so its certainly not that! If anything I think it might be your card thats letting you down.
With all my tweaks I run, PMDG 737NGX with REX 2.0 and ezdok no problem at 30fps.
Hope that helps a bit!