Just installed Windows 10 the second time. First I installed it with the Bios set to "Legacy" boot. Took my new Kaby lake 22 seconds to boot to Win10.
I realized that something was wrong knowing the specs...
Gigabyte Z170 Gaming 7
M.2 256GB drive as my boot drive on PCI-e 32Gbps
Samsung 512 Sata SSD as my D: drive strictly for data
16GB Corsair vengeance ram PC2133
eVGA GTX 1060 GDDR5 6GB ram
So putting the OS alone on an M.2 should boot much fast, so after researching the crap out of it, I knew I had to enable UEFI in the bios and reinstall Windows.
I did and now my boot time is around 6-7 seconds.
What about you?
I wish I could afford a GTX 1080TI LOL, one day.