How many wires does each PCle lane have?

Two wires would provide only a single differential pair, enabling only one-directional communication and preventing the full-duplex operation that PCIe requires.

Each PCIe lane consists of two differential signal pairs - one pair for transmitting (TX+ and TX-) and one pair for receiving (RX+ and RX-), totaling 4 wires per lane. This design enables simultaneous bidirectional data transfer on a single lane without collision. The differential signaling method also reduces electromagnetic interference and improves signal integrity at high clock speeds.

Eight wires per lane would represent a parallel bus or multi-lane grouping, not the architecture of a single serial PCIe lane.

Sixteen wires per lane corresponds to wide parallel bus designs and has no relationship to the serial point-to-point architecture used by PCIe.