There we go then, clear evidence that the reference PCB is incapable of supporting a mass produced overclocked edition, even with overclocks that small.
The gigabyte is better than the KFA2, but not by much. The gigabyte is few degrees cooler after the KFA2 cooler is properly reseated, and both seem to be managing a minimum overclock across every card of 1250 Mhz.
Every KFA2 EX OC is running perfectly out of the box at 1215 Mhz with no hassle, it looks to be well worth the cost over the best reference design card from EVGA. The only problem is that the KFA2 needs the cooler to be reseated for acceptable temperatures, but the gigabyte doesn't and still has lower temperatures.