I am not going to say how much I've spent over the years (don't want to look or know), but I will say this. The next time you are considering a new graphics card, CPU, etc. for FSX, consider the value of your investment and how these parts will help you get the most out of them.
In other words, why not just splurge for the 780 or Titan? You know you deserve it. And, you can justify the cost by lying to yourself that it is needed to justify all the other money you've spent on FSX. A Titan can help you maximize the money you've already spent.
And seriously, since I splurged for the 4770k and GTX 770, my investment in FSX has never felt so justified. I am seeing this sim the way the original ACES team thought about it. FSX has finally started to fulfill the dreams that the original visionaries had.
You owe it to yourself! lol