it seems (to me) very interesting, that these Areca RAID NVMe cards (and even cheaper ARC-1686 xNOD ones) are compatible not only with new systems with uEFI BIOSes, but also with old systems with "Legacy INT13" BIOSes. And Areca even claim compatibility not only with PCIe Gen3-2-1, but also PCIe x8, x4, x1 (of course with the influence towards overall speed performance).
It also COULD BE possible to force archaic systems (like socket 775) with old BIOSes without NVMe boot support to force them to boot such NVMe SSD disks through "SCSI card" or "add-in card" boot feature in BIOS
, which is practically impossible with any non-RAID NVMe cards (without difficult manual BIOS mod injection).
I think such PCIe NVMe RAID cards (regardless their relatively high price) should be good for users of old systems preparing to migration to next-gen PCIe G4 SSDs and mobos in the future.