Btw, afr and afr2 should produce microstutters by its nature and should be unuseful for newer games, as far as I am informed. The dynamic texturing methods and various effects should make afr amd afr2 obsolete, because it works different and is not really compatible to some graphics featires (e.g. volumetric clouds, dust...).
I think, that this is, why you get the stutters. It could reduce in this mode, if you experiment with switching off some features (which is not intended by you anyways, I think).
Would be interesting to compare generally a performance increase with the same settings, and not switching to higher resolution or more graphic details. Otherwise this sli is like I already mentioned. More fps, but more problems...
I can live with my 50-70 fps average on my unboosted card