Yeah the one plus side to the Gigabyte cards is they never seem to throttle and clock the highest. Of course they use like 10-15% more power then all the other cards, so...
As I said, my Zotac card start to mine quark at 15.5 mhash, and then it trottles and fall down to 13.5-14. My gigabyte is stable at 17MHASH. 3,5 MHASH bether.