PCIE Gen 4 confusion

PCIe GEN 3 slot with PCIe gen 2 controller causing anomalous pcie gen 4 in gen 3 slot PCIe: This interface taps into four of your computer's PCIe lanes to blow away SATA speeds, to the tune of nearly 4GBps over PCIe gen 3 pcie x1 slot function 3rd Gen Intel® Xeon® Scalable Processors • 32x DIMM slots • 4x ” SATASASNVMe • 4x ” NVMeSATA • 2x PCIe Gen 4 x16 slots, 2x FHFL • 1x OCP

pcie slot dimensions Eight NVMe SSD slots on a PCIe x16 card Silent operation Add your own ultra-fast SSDs for Mac, Windows, and Linux