Why PCI Express backplanes are so expensiveunpopular?

Why PCI Express backplanes are so expensiveunpopular? pci 4 in pci 3 slot 2 slots Some of those slots share PCI lanes with the PCIe slots In the one you mentioned it appears that the 3rd slot (M2C, likely means there pcie slot width Shop 4 x PCI Express x16 Intel Motherboards on Watch for amazing deals and get great pricing

pcie slot width Limiting the PCI Express interface to Gen 3 meant that the available bandwidth dropped to GBs In other words, using PCIe 4 means that

pcie 4 in pcie 3 slot ssd May well be as it is working fine in PCIE x16 slot three off the chipset and PCI E x16 slot one is CPU may be the odd chance CPU is not seated SYONCON PCIe Multiplier, PCIe Splitter 1 to 4 PCI-Express 16X Slots Riser Card, PCI-E 1X to External 4 USB Adapter for BTC Miner Machine GPU Mining ·