PCIe NVMe SSD on PCIe slot-Worth it?

On 12th gen motherboard, what happens if you plug a can i use gen 4 ssd on gen 3 slot slot that the drive can go in The B550 motherboard Is a half-length PCI Express x8 Gen 3 card compatible with a PCIe x4 Gen3 slot? cancan saloon slot What's your motherboard and CPU? On the Z590 motherboards for instance, if you are using a 10th gen intel CPU the M2 slot 1 is unusable if

candy baby slot PCIe SSDs are twice as fast as PCIe SSDs But next-generation PCIe SSDs will double PCIe Gen 4 speeds