You will not gain much with a bigger graphic card with FSX/FSX:SE. I went from a 960 GTX 2Gb to a 1060 GTX 6Gb because of X-Plane. And when I tried FSX:SE I did not see any
change in performance. Only thing was that I could turn up things in nvidia inspector. No more FPS.
It is CPU bound. If you thinking of changing plattform check out X-plane, there you gain hot graphic cards.
I did it on a boring weekend and I'm stuck with it now. First of all no other flightsim today can beat it's aerodynamics. As close to reality as possible. Just surf around and check videos and forums about it. If you know about the famous youtube star Captain K he have moved to X-Plane because it is outstanding as he says. I did not like the versions before 11, the scenery looked crazy but now from ver 11 it is based on Openstreet maps and the default is very good. Lots of freeware scenery/airports and many have very high quality. Almost level with payware and you can create airports like that yourself for free. Or fix some. It is also developed whole time, adding more stuff whole time. One of the latest things in aerodynamics is Downforce over wings.
One of first things I bought was IXEG 737 Classic(300) and it is at PMDG level and quality. But because of the superb aerodynamics it took me a lot of practice to fly the approach by hand
and do a nice flare. I just did not work to handle the plane as I did with PMDG 737, especially the flare. You are really flying. It is a true 64 bit using the GPU for the graphic work. And a lot of
things are totally dynamic, eg. change time of day minute by minute or hour by hour with a button in middle of the flight, cool. Night lightning is just WOW, check it.
Give it a try. There is a free demo version, limited area. And if you buy it just enter the code to activate it.
I have long time ago put P3D aside. It is just FSX with another name and far to expensive.
I have no relationship to Laminar and X-Plane, I just happen to love it and think that it is the next generation of flightsim. Still have some minor flaws but are getting better whole time, only
month between upgrades.