I'm new to hardware, and at the moment I'm planning my very first build.
In the process, I just realized that I have absolutely no idea how PCI lanes are allocated, or about how they and function. I just discovered something that seems so contradictionary and broken that it can't possibly be true, and hence comes my confusion. Firstly, here is the relevant CPU, and the motherboard that I'm looking at:
http://ark.intel.com/products/75462/
http://www.asus.com/Motherboards/P9D_WS/#specifications
The Xeon E3-1245 says this of itself:
"Max # of PCI Express Lanes: 16"
Yet the motherboard, which has the C226 chipset specifically designed exactly for this Xeon E3-1200 line, says of this of itself:
"3 x PCIe 3.0 x16"
I've checked, and there no Xeon E3-12xx which lists more than 16 PCI-e lanes in its specifications. For a moment I thought that perhaps the i7 4th Gen, which this ASUS board also takes, was perhaps the chip with more than 16 PCI Express lanes. But then I went and had a look at every single i7, and none of them do.
Even more puzzling to me is that people regularly put multiple 16x PCI-e 3.0 GPUs into these things with SLI or CrossFireX, and the ASUS board's spec page even emphatically declares that it has good CrossFireX support. How can that be when the CPU claims to have only 16 lanes?
Moreover, any old single graphics card is likely to match to the CPU's 16 PCI-e slots right off the bat, and there where is there room left for even smaller expansion cards?
I must be really misunderstanding something about what it means for a CPU to "Have 16 PCI-e Lanes," it can't possibly mean what I think it does.
Very confused,
Many thanks for reading,
-Patrick
In the process, I just realized that I have absolutely no idea how PCI lanes are allocated, or about how they and function. I just discovered something that seems so contradictionary and broken that it can't possibly be true, and hence comes my confusion. Firstly, here is the relevant CPU, and the motherboard that I'm looking at:
http://ark.intel.com/products/75462/
http://www.asus.com/Motherboards/P9D_WS/#specifications
The Xeon E3-1245 says this of itself:
"Max # of PCI Express Lanes: 16"
Yet the motherboard, which has the C226 chipset specifically designed exactly for this Xeon E3-1200 line, says of this of itself:
"3 x PCIe 3.0 x16"
I've checked, and there no Xeon E3-12xx which lists more than 16 PCI-e lanes in its specifications. For a moment I thought that perhaps the i7 4th Gen, which this ASUS board also takes, was perhaps the chip with more than 16 PCI Express lanes. But then I went and had a look at every single i7, and none of them do.
Even more puzzling to me is that people regularly put multiple 16x PCI-e 3.0 GPUs into these things with SLI or CrossFireX, and the ASUS board's spec page even emphatically declares that it has good CrossFireX support. How can that be when the CPU claims to have only 16 lanes?
Moreover, any old single graphics card is likely to match to the CPU's 16 PCI-e slots right off the bat, and there where is there room left for even smaller expansion cards?
I must be really misunderstanding something about what it means for a CPU to "Have 16 PCI-e Lanes," it can't possibly mean what I think it does.
Very confused,
Many thanks for reading,
-Patrick
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