I can confirm a stuttering gSync issue in WoW in any nVidia driver past 452.06, when they started updating the drivers for the new 3xxx series of cards. If you revert back to version 452.06, the gSync stuttering magically vanishes.
I can confirm that I just tried 457.30, get a massive stuttering issue, and revert back to 452.06 and everything is better.
nVidia has not solved this issue for months. They dont acknowledge it. I have a 1080ti and cannot upgrade even if stock existed, because I would need to upgrade the driver in order to use the new card, and games would be broken.
For now, try using 452.06 and see if that works for you.