I'm posting this since I haven't seen this suggestion anywhere else.
I rolled back from nVidia driver 344.75 to the previous one (344.60).
This driver doesn't officially have a SLI profile for Far Cry 4.
However, if you use nVidia inspector and set dx11 bits to Far Cry 3 it might just work for you too.
Every kind of stutter is gone ... and this is after trying everything else.
Annoyingly simple, right?

Hope this helps!

PS! I also set power management in control panel to max. Haven't tested if that does anything at all. Just a FYI.

My system:
Intel i7 first gen, 2,67 OC'ed to 4,10 on ASUS P6T MB
12 gigs RAM 1600MHz
Geforce 680GTX 4 gigs in SLI
WD SATA 7200rpm HDD