New Gigabyte Z170X Gaming 7 build posts twice from cold boot - 1 short beep, several seconds if silence, 1 short beep then boots in to windows

[TongaKid]

I built a new Z170X Gaming 7 based system last week - everything seems to be working fine, I've had no crashes, everything seems stable, but the system has taken much longer to boot than I feel like it should and the boot splash screen for the MB flashes once during booting.
So, today I put an old motherboard speaker in to the system and when I powered it on I got the everything-is-good 1 short beep, a few seconds of silence and the motherboard splash screen disappeared, then reappeared, then a heard 1 short beep again - then the system booted in to windows correctly. The error codes on the MB's LED flash so fast I have no idea if any are actually issues, and when the system is booted in to windows it shows "bF" or "6F", I can't tell which, but both aren't listed as an error code in the manual.

This doesn't happen on a restart. Only booting from the system being turned off.

I really have no idea how to proceed with this, so any help would be hugely appreciated.

Build:
Z170X Gaming 7 bios version F5
i7 6700K
16GB DDR4 Corsair
Samsung 950 Pro M2 512
2 GTX 980ti's in SLI
Corsair HXi1000i PSU
Corsair H80i Cooler

[Bobes]

Re: New Gigabyte Z170X Gaming 7 build posts twice from cold boot - 1 short beep, several seconds if silence, 1 short beep then boots in to windows

Update Bios to F6f

F5 was no good for cold start for me either i had a thread on this ages ago i thought it was my Intel 750 pcie HDD but its all to do with bios -


GIGABYTE - Motherboard - Socket 1151 - GA-Z170X-Gaming 7 (rev. 1.0)

Also the latest windows 10 update has fixed the fast boot issues - i was never able to fast boot or ultra fast boot now i can

My system is identical to yours without the HDD and gtx980 SLI config just running one and you wont be disappointed