Speed Difference with Fiber Optic MXI Cable

Updated Jun 15, 2018

Reported In


  • PXIe-8381
  • PCIe-8381

Issue Details

I am putting together a quote for a Gen 2 x8 MXI card and corresponding cable. I noticed that the cable shows up with the following description: MXI-Express Cable, Gen 2 x8, Fiber Optic, 30m (Gen 2 x4 Speed). Is the speed of this cable slower than x8? Why is this?


This cable can only transmit data at the same speed as a Gen 2 x4 copper cable (1 GB/s). However, the connector is still a Gen 2 x8 connector, meaning it still fits in a Gen 2 x8 card, it just transmits at half the speed of a Gen 2 x8 copper cable.

Additional Information

In general, Fiber Optic cables are able to go longer distances, but using fiber optic causes a speed reduction. Copper is recommended if you are able to reduce the distances to the length of a copper cable.


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