I'm pretty sure the only SLI setup that actually reduces microstuttering is the GTX690 and that's because it's not burdened by the PCI-E bus on the motherboard, instead making do with a lower-latency, dedicated bridge on the board. Anyway, if you can afford a GTX690 you can afford to have your butler play your games for you whilst you snort a line of cocaine off a supermodel's navel, making it a moot point
I have to admit, the prospect of a 7950 ever being better than a 7970 did seem unlikely. I had things like "If the 7970 is both TDP-limited and not effectively using the extra shaders, disabled shaders might allow higher clockspeeds"
as a theoretical answer to Shaq's statement but even in my head that seemed doubtful;
A 7950 is a castrated 7970; At best it's missing part of its manhood
At worst it's on a smaller, inferior board using fewer, cheaper VRM's and a smaller, less expensive cooling solution.
It could also have a voltage-leaking Tahiti core that failed to meet the clockspeed binning requirements of a 7970 and is on the raggedy edge of the functional/defective divide.
I'm sure that's faster than a full-blown 7970. Definitely, in fact.