I see the same issue, although I'm still on my 950 Pro as my boot drive. My last boot time shows 15 seconds and then 8 seconds from the time the Windows logo appears to the login screen appearing. I've never looked at last boot time on my previous 840 Pro, but I have timed it from cold boot at around 8 to 10 seconds from the time I tapped the power button to typing my password at the Windows login screen. So, I agree with others that it's nvme causing the bios delay or likely the mobo patchwork to enable nvme support.
I don't reboot a whole lot unless I'm playing with fan profiles and saving and loading bios configs, but during those times rebooting becomes painful. I guess my solution is to throw in an 850 Pro as a boot disk and use the 950 as storage and for running my VMs.