Solved: SSD —PCIe 3 or PCIe 4 - HP Support Community

You're referring to NVME based M2 SSDs, correct? But yes if the SSD is PCIE spec then of course the speed will be less when used on PCIE

They are all compatible Even a PCIe SSD will work just fine, but the speed will be limited to PCIe x4

m2 slot mainboard When installed in a Windows PC's PCIe slot with four SSDs formatted in a RAID 0 configuration, the card is capable of 8,500 MBs transfers Aggregate

m2 slot types So, the PCIe or third-generation card will function when installed in a PCIe or second-generation slot as the PCIe standard is such that it is both