What are the differences in performance and architecture between PCIe and QPI?

Question

PCIe 3.0 x16 and QPI 1.1 (20 lanes) have the same effective bandwidth (16 GB / s). So, I wanted to get a rough picture of the differences between them.

What is the difference between these two factors in terms of latency and message rate (number of packets or TLP per second)? For latency, my ball numbers are 20 ns for QPI and 200 ns for PCIe 3.0. Are these good grades? If so, why is the PCIe delay much higher - is it because of the length of the wire?

Are there significant architectural differences between the two, besides QPI that provides cache tracking? As far as I know, both use a layered protocol: the transport layer through the physical layer.

Answer 1

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GT/s. QPI: 4.8, 6.4 8 GT/s 5 8 GT/s PCIe.

, , . QPI . , 4+ QPI . PCIe 500ns, . PCIe, ( PEG), , , .