Running Ubuntu 16.04 current of today (4.4.0-15-generic #31-Ubuntu SMP Fri Mar 18 19:08:31 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux) with a Asus z170i pro gaming that comes with the "Qualcomm Atheros QCA6174 802.11ac Wireless Network Adapter (rev 32) [168c:003e]" I got wifi-ac working just by adding the board-2.bin file, unload ath10k_pci and ath10k_core, load ath10k_pci.
Running Ubuntu 16.04 current of today (4.4.0-15-generic #31-Ubuntu SMP Fri Mar 18 19:08:31 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux) with a Asus z170i pro gaming that comes with the "Qualcomm Atheros QCA6174 802.11ac Wireless Network Adapter (rev 32) [168c:003e]" I got wifi-ac working just by adding the board-2.bin file, unload ath10k_pci and ath10k_core, load ath10k_pci.
sudo wget -O /lib/firmware/ ath10k/ QCA6174/ hw3.0/board- 2.bin https:/ /github. com/kvalo/ ath10k- firmware/ blob/master/ QCA6174/ hw3.0/board- 2.bin?raw= true
sudo rmmod ath10k_pci ath10k_core
modprobe ath10k_pci
Monitoring the connection in my router I can see up to 866.7Mbps, though cifs file transfer speed is just about 100Mbps.