Are My Mac Pro Expansion Slots PCIe 2.0 or 1.0?

Every Mac Pro comes with four expansion slots on the motherboard, which can easily be accessed by taking off the side panel of your machine. Your graphics card will be in slot 1, which is double wide.

MacProExpansionSlots

PCIe 2.0 (PCI Express version 2.0) supports double the transfer rate compared to PCIe 1.0.

MacPro 4,1 (2009) and 5,1 (2010):

  • Slot 1: PCIe 2.0 (x16)
  • Slot 2: PCIe 2.0 (x16)
  • Slot 3: PCIe 2.0 (x4)
  • Slot 4: PCIe 2.0 (x4)

Mac Pro 3,1 (2008):

  • Slot 1: PCIe 2.0
  • Slot 2: PCIe 2.0
  • Slot 3: PCIe 1.0
  • Slot 4: PCIe 1.0

Mac Pro 1,1 (2006) and 2,1 (2007):

  • ¬†All Slots PCIe 1.0

Not sure which Mac Pro model you have?

PCI Express Lanes

What does “(x16)” mean? “x16”, pronounced “by 16”, refers to 16 lanes of connectivity in the slot. A 16 lane connection has 2 times the transfer rate of an 8 lane slot. This lane limit per slot is hardwired in the 2009 and 2010 Mac Pro models. Therefore, if you want to plug in an expansion card that takes advantage of more than 4 lanes, you would want to plug it into slot 2 (since slot 1 is already being used by your graphics card).

In the earlier Mac Pros, you can use the Expansion Slot Utility to alter the distribution of lanes across slots.

 

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