The 690 is the equivalent of 2x 680 -5%. If the FPS between a 680 and 690 are not much different i'd be inclined to put the current generation of games as the culprit, 6 months or so will solve that gap. I would doubt the CPU would be that responsible for the bottleneck in the 690 vs 680 FPS difference. I'd love an answer on this though, if you could let me know it would be great.
EDIT: Found a relevant benchmark:
"
Before we start of our regular benchmark run I decided to try the GeForce GTX 690 on a couple of platforms. Mind you that we had roughly a day to do this entire article so really this was the maximum I had time for.
In our recent GeForce GTX 680 SLI article we already mentioned that as long as you have a modern age processor, preferably Intel Core i7 based, then it really doesn't matter that much what kind of processor you have and how high it's overclocked, unless you want an influence on the 3DMark series."
http://www.guru3d.com/articles_pages/geforce_gtx_690_review,12.html
EDIT 2:
More research and it turns out the x58 chipset being PCI-E 2.0 limits the 680 and 690 by about 1% on average because of the extra bandwidth of a PCI-E 3 slot not being available. That is not anything to be concerned with.
The CPU bottleneck appears in something like Battlefield 3 where the game is quite CPU intensive. Running a 3.33Ghz w3680 appears to bottleneck performance in these types of games. Have I hit a wall? Many people are saying they overclocked their stock i7-980x to 3.7Ghz and the bottleneck is solved. Does anyone know the real world performance hit? CPU bottlenecks become non-existent at higher clocks, 3.7Ghz seems to be the sweet spot right now for removing that limit, my processor is around about 400Mhz below this, could 400Mhz make that much of a difference? The turbo on my processor is 3.6Ghz on a single core, I believe. 3.46Ghz on all 6 cores? Can a game utilise more than 4 cores?
I guess what i'm asking is, will my 3.33Ghz processor paired with a GTX 690 = incredible performance? Does 400Mhz and upwards make that much difference? The article I linked to says at a certain point it doesn't, 400Mhz??