NVMe adapter for 4 drives

PCIe is backward compatible It's also forward compatible So, you can insert PCIe expansion cards into PCIe slots, but your data

NVMe adapter for 4 drives 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

PCIe is backward compatible It's also forward compatible So, you can insert PCIe expansion cards into PCIe slots, but your data

pcie 30 x1 slot If B 550m Pro4, the second slot is , not Don't blame the product for what you don't know Specifications Model NVME SSD to PCIe

PCIe x4 slot with Lower impedance CONNECTIVITY Dual NVMe PCIe * Connectors

pcie x32 slot 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

PCIe x4 slot with Lower impedance CONNECTIVITY Dual NVMe PCIe * Connectors