Re: support for bootable pcie ssd on older hp z620?

I successfully installed a Samsung 256GB SM951 as a (UEFI) boot drive in my Z620. It also has 2 x E5-2670 v1 CPU's.

Possibly of interest;

http://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/SM951-M-2-SSD-in-a-HP-Z620/m-p/5708010/highlight/true#M13409

My system was able to boot from the SM951 in legacy mode and also via the Windows Boot Manager (UEFI) boot. I'm not sure if an NVMe drive will work as I have the AHCI version. My ASUS PCIe card is installed in slot 4 on the motherboard.