ASRock B450M Pro4 PCIe 2.0 for boot drive£

Hello there!

I have an ASRock B450M Pro4 with a WD Black SN850X installed in the Ultra M.2 Socket as only storage medium currently in the system.

To be able to work from home I received a Samsung 970 EVO Plus SSD with a separate Windows installation. The intended usage is that I install the drive into my system and boot from that drive when working on my PC such that work and play is kept seperate.

Unfortunately, the other m.2 slot on the motherboard supports SATA3, not PCIe. Instead of having them buy another SSD and transfering data, maybe using a PCIe adapter might be a simple and cheaper solution.

The only available PCIe slot in my system is the PCIe 2.0 x16 Slot as the PCIe 3.0 slot is occupied by my graphics card and the space behind the PCIe 2.0 x1 is blocked by the heatsink of the WD Black SN850X. To prevent blocking the air intake of my GPU I currently looking at this adapter: https://akasa.co.uk/search.php?seed=AK-PCCM2P-05

HOWEVER there is some wording in the manual that has me confused, hence this post. In the manual (https://www.asrock.com/mb/AMD/B450M%20Pro4/index.asp#Specification), under the 'slots' header it shows the following:

- 1 x PCI Express 3.0 x16 Slot (PCIE2: x16 mode)*
- 1 x PCI Express 2.0 x16 Slot (PCIE3: x4 mode)
*Supports NVMe SSD as boot disks

Does this * imply that only the PCIe 3.0 slot can be used with such an adapter to install a second bootdrive into my system? I am not technical enough to see a reason why I might not be able to boot from the PCIe 2.0 x16 slot.

If relevant, I have a AMD Ryzen 2600X CPU and Nvidia GTX 1070 graphics

lessew wrote: Does this * imply that only the PCIe 3.0 slot can be used with such an adapter to install a second bootdrive into my system?

That is how I read it.
I've only used the 1st slot.