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Question: Mac Pro 5.1 PCIe Link Width

I just bought an x16 Asus nvme controller and I dropped it in to a x16 slot and I only got x4 link width and 2.5GT speed. It will only read one of my 2 nvme drives but the point of the x16 card is that it's supposed to read all drives.

I tried changing slots with the video card and still don't work.

Can anyone help getting my X16 slot run at x16 speeds?

Thank you


Mac Pro, macOS High Sierra (10.13.1)

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Nov 15, 2017 2:25 PM in response to Detra17 In response to Detra17

The Mac Pro 5,1 has two x16 slots (the ones toward the bottom of the chassis. The other two have full width connectors, to support any card you might like to place in them, but they are x4 slots. this is how Apple says it:

PCI Express expansion

  • Three open full-length PCI Express expansion slots5
    • One PCI Express 2.0 x16 slot
    • Two PCI Express 2.0 x4 slots
  • All slots provide mechanical support for 16-lane cards
  • 300W combined maximum for all PCI Express slots


Mac Pro (Mid 2010) - Technical Specifications


Nov 15, 2017 2:25 PM

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Question: Mac Pro 5.1 PCIe Link Width