Maybe the update gives more hashrate?
Or maybe the update is just a ploy by some miners at Microsoft to lower the difficulty of their favorite coins by getting everyone else to turn off their rigs for an hour.
Some gamers insist that every video device driver update improves their frame rates, but I haven't seen that translate very well to improved hash rates. But if anyone wants to update both their OS and their device drivers, now would be the time. Is .1709 a new Creator's Update?