So, "Good" news/Bad news:
The bad news:
The B-85 Chipset can support the USE of a PCI nvme (or whatever is connected to PCI) but not the booting from that NVME. To do that, special tricks must be made which to be honest not sure it's worth the time but I will share anyway. The second issue is that your mobo on the PCIe slot of your mobo supports only up to PCI v2 X4, and that means that even tho your NVMe disk will probably be faster than your SSD, it won't be by that much, At least the NVMe can later be used on a newer PC at full speed so it doesn't really matter much. Just pointing this out in case you do tests and don't see the advertised speeds, not to worry that the disk is bad or has issues.
Before I start, my suggestion would be, to use your regular SSD to ONLY boot windows, and use the NVME for applications, games, and in general files that need the extra speed. That way you can test, and switch windows build, or even multiboot, and not have to worry about your files since they will be on a different disk, and on top of not going through the hassle, you are about to read, to install this or new versions of windows.
"Good" News:
As
@kingkenny said above you can read this link
https://winraid.level1techs.com/t/guide-nvme-boot-without-modding-your-uefi-bios-clover-efi-bootloader-method/31665
and it describes how by using an external bootloader on a USB thumb drive or any other boot capable device, (I even did it with a floppy disk in the past), you can boot from PCI, but as I said above, not sure it worth going through that trouble to save a second or 2 from booting.
Just for trying it, I also assume you checked and disabled CMS and/or secure boot (however your mobo calls it) and disconnect all other drives? I doubt it will work but... you never know. Additionally, check if any new bios do support NVMe but intel was clear that anything below z97 will not get NVMe boot support. Having said that you may search for a Modified bios that does support NVMe but the risk is all yours.
Hope it helped and I wish there was a better solution for you.