Al,
Where are you getting odd pauses? FSX, or other applications? Remember, FSX is a 32 bit application and, depending on what you read, can't use more than 4 gb of ram. If you're looking for more speed and fewer pauses (or stuttering) then more ram than you already have won't make any difference. Stuttering can be caused by numerous things, but with a LOT of patience and experimenting can be reduced if not completely eliminated with a properly tuned system. Also, FSX is a very CPU intensive application and for the most part the faster the CPU speed, the smoother FSX will run. FSX run with Steve's DX10 Fixer will shift more of the CPU load to the GPU for a smoother experience. However, the DX10 Fixer takes some time to set up and fine tune as well.
That's a lot of money for that kind of upgrade, in my opinion. While the 980 would be really sweet it's probably overkill for what you need. You'd be better off going up a step or 2 to a 2nd generation video card and upgrading your CPU to something that will boost your clock speed to at least 4 ghz or more, if your MBO can handle it. My opinion only and there's a million philosophies on the topic and there's a ton of info on the topic out there.
FWIW, I only have 6 gb ram and an Intel I7 950 CPU overclocked to 4.12 ghz. running FSX with Steve's DX10 fixer and an Nvidia GTX 760, sliders set per ORBX recommendations. Does fine for 99% my type of flying.
If you get annoying stutters, I'd be glad to work with you privately on this.