What is PCI Express? Do PCIe lanes, slots, and versions matter?

An x4 PCIe device has a theoretical max transfer rate of MBsec according to wiki

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

pcieslot PCIe 's throughput is 1GB per second per lane, providing an overall data transfer rate or bandwidth of up to 32GBs total PCIe doubles

pcie 4 in pcie 3 slot PCIE x2USB I2CDisplayPort x4, WiFiBluetoothWWAN B, 2230, 2242, 2260, 2280, 3042, 22110, PCIe x2USB USB AudioPCMIUMSSICI2C, SATAPCIe