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"PCI Express Configurations"

Last response: in CPUs
September 22, 2012 9:16:16 PM

I am planning on buying an i5 3450 for my new pc but I noticed something that I don't understand on Intel's website...
It says in about the middle of the page "PCI Express Configurations : 1x16, 2x8, 1x8 & 2x4". Does that mean that if I use a graphics card on the x16 slot then the rest of the pci-e slots are useless because the cpu can't handle them? The mobo I going to buy is the Asrock H77 Pro4/MVP.


a c 116 à CPUs
September 22, 2012 9:34:47 PM

The main PCIe controller is integrated into the CPU and has 16 lanes which are all mapped to the x16 slot on most boards. On SLI/CFX boards, those lanes may be either hard-wired for x8x8, x8x4x4 or have PCIe multiplexers to re-route 8 lanes from the x16 connector to the 2nd x16 connector to switch between x16, x8x8 and possibly x8x4x4 configurations.

Most motherboards implement x16 / x8x8 using muxes instead of hard-wired.

The other (non-x16) PCIe slots are connected to the IO Hub's PCIe 2.0 lanes. Since the IO Hub has only 8 lanes and at least one of them is usually taken by the GbE chip, the other PCIe slots are usually x4x1x1
a b à CPUs
September 22, 2012 9:45:23 PM

yes. ^ +1 to him. in other words, no, your other PCI slots aren't useless. you can sli or have any other PCI add ons as long as they are up to specs. that mobo has 1 16x PCIe 3.0 slot, meaning you can have 1 GPU because the other PCIe slot is 4x speed and 2.0, meaning its operating at a too of a slow speed to fully take advantage of another GPU, it would be a waste of money. but, you can pop other PCIe add ons into that as long as it can operate at PCIe 2.0 x4 speeds.