Hello,
From my experience, it's a bit of trial and error but here's what I did to get faster boot time.
There is an option to enable fast boot in the UEFI bios. Use it.
Same for ram, I activated fast boot on it.
Third, there is an option to specify which windows version you use, I noticed a small improvement by putting Windows8/10 in there.
There is also an option to choose which PCie slot is going to be looked up first to display on startup. Choose the one where you Gfx card is in. ( Should be the first or second)
On the top of my head that's all I can think off !
Good luck.