PCIe Gen 4 vs Gen 3: Do you need to spend extra on SSDs?

Sonnet 8x4 Silent Gen4 PCIe Card m 2 gen 4 in gen 3 slot Learn to distinguish cards, including slots, keys, sizes, and types Understand slot functionality, and PCIe interfaces, and the platform's m2 expansion slot Solved: Does installing gen4 NVMe SSD on PCIe 3 slot affect the speed? or should i buy 3 gen3 NVMe ssd? Please give me some advice

m2 sata slot 1x SSD slot , 1x SSD Combo (NVMe PCIe Gen3 1x 2280 NVMe Gen 3 slot + 1x 2280 Gen 4 ; 1x 2280 NVMe Gen