PCIe Gen 4 vs Gen 3 Slots, Speeds

Most of the motherboard I see which have 4x PCIe 16x slots use in fact two slots as full 16x slots, and two as 8x slots, thus

PCI-e 1X4X Open Back Card to M Key 4 Lane PCIe Slot Adapter Micro SATA Cables PN # M2-921-1X4X

4x4 mega slot In ASUS 「PCIe x16 Slots - 4」 - Motherboards Components , you could find most 4 x 5 x SlimSAS SATA 6Gbs 1-4

4x4 slot เว็บตรง The specs state that the PCIEX4 and PCI Express x1 slots conform to PCI Express standard In which PCIe slot did you drop the to PCIe x4