If I had a Titan, I could care less that a pair of 7970s is putting X% higher frame rates, when I know it isn't perceived as such. If it's not releasing frames in nearly consistent intervals, then you're going to perceive the longer frame outputs. But when running at a higher frame rate, it's less noticeable, because it's like comparing 60 to 80fps, which imo, is far less less noticeable than the difference between 30 to 40fps.
So many don't realize this, and never take it into account, because multi-GPU setups are usually completely overkill. You have people here running SLI and CF on 1080P. And in your case, well, you're running quad-CF, and I remember reading an article at [H] a long time ago that showed MS to actually decrease as you added in more cards. So while you lose scaling per card, you also somehow remove the MS as well (don't remember the exact details of the article).