Dual Booting Mac OS Catalina and Windows 10 on separate NVMe SSDs

[snodaze]

Hi guys I have been doing a lot of research and going though guide after guide, however I am at a stand still on being able to get this to work. I have a total of 3 NVMe SSDs. One being my Hackintosh drive working. One my Windows 10 drive working. The third is a fresh SSD I purchased to try and figure this whole thing out. My problem is that with 2 NVMe SSDs installed to my mobo my PC will not get into the bios. No matter what I install. Whether it be Hackintosh drive and Windows 10 drive, my Hackintosh drive and blank drive, or my Windows 10 and blank drive. Every guide I've gone through that talks about dual booting on two separate drives makes it seem like this should be a cake walk however nothing has worked for me. What am I supposed to do?

PC Specs:
MOBO: Gigabyte Z490 Vision D
CPU: Intel i9 10900k
GPU: Sapphire Pusle RX 580
SSDs: Western Digital Black (1tb blank, 1tb Hackintosh, 500gb Windows 10)

 

[Going Bald]

Suggest you install the Win10 drive in the slot between the x8 and x4 PCIe slots. According to the manual this slot goes directly to the CPU via PCIe bus sharing lanes with PCIe4 slot (lowest slot in your last pic). This slot is likeliest to be the first slot the BIOS looks at for a boot drive. Then install the Mac drive in the top slot (this will make the SATA slots 0 & 1 unusable for SATA connected devices, so make sure nothing ever connects to these two slots.
The third drive can be connected to the center slot, making SATA slots 4 & 5 unusable for SATA connected devices, so make sure nothing ever connects to these two slots.

Note that the SSD in the PCIe bus slot MUST BE PCIe capable and labeled as such to work in this slot.

As for not being able to boot to BIOS with 2 drives installed at one time, this is a problem for which you need to contact Gigabyte support.