What is the maximum read and write speed for pcie x4 slots?

x4 PCI Express to PCIe SSD Adapter pcie 3 0 x4 slot Supports PCIe motherboards and is backward compatible with PCIe and PCIe ; also supports PCIe x4 bus slot and is compatible with x8 x16 bus slot pcie slot sizes NVMe PCIe® x4 & PCIe® x2 • 1x PCIe ® Slot 2 2280 • NVMe PCIe x4 and SATA Mode 12 Smart Fan 5 + FAN STOP • 3 Fan

pcie training error slot 1 interface utilizes multiple technologies, including x2 to x4 PCIe Lanes, NVMe , SATA protocol, and USB