At a higher level, considering that all protocols are serial these days, how does a multi-lane protocol (PCIe x4 or x16, Ethernet x4) use the multiple lanes, is it multiple independent requests going on each lane?
PCIe "shreds" each packet across multiple lanes to reduce latency.
Generally, if you are wondering what PCIe does, the answer is usually "they do the hardest, fastest, highest-performance thing and they do it so well that nobody notices."
