PCIe 2.0 And PCIe 3.0 Expansion Options - Compatibility ??

Started Mar 5, 2013 | Discussions thread
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BPB
BPB
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PCIe 2.0 And PCIe 3.0 Expansion Options - Compatibility ??
Mar 5, 2013

I have been looking at various cpu’s, motherboards, chipsets etc. etc.

During this process I have become aware of the different PCI/PCIe expansion types of slot/card/cpu specs. And I am (again) suffering a “senior moment”

The Intel website shows the following details for CPU Expansion Options,

PCI Express Revision,

Sandybridge E  i7 3820   PCI Express Revision 2.0

Sandybridge E  i7 3930   PCI Express Revision 2.0

Ivybridge i7 3770K         PCI Express Revision 3.0

When it comes to motherboards from most manufacturers, the specifications show a variety of expansion slot options, for example,

The GIGABYTE GA-X79-UD3 Intel X79 (Socket 2011) Motherboard shows that it has,

Expansion Slots Total (Free)

2 x PCIe 3.0 x16 (running at x16)
2 x PCIe 3.0 x16 (running at x8)
2 x PCIe 2.0 x1
1 x PCI

And the ASUS P8Z77-V PRO Intel Z77 (Socket 1155) Motherboard shows,

Expansion Slots Total (Free)

2 x PCIe 3.0 x16 (running at x16)
1 x PCIe 2.0 x16 (running at x4)
2 x PCIe 2.0 x1
2 x PCI

Also when it comes to graphics cards they are shown as either PCIe 2.0 or PCIe 3.0.

MSI GeForce GT 630 4GB GDDR3

810MHz Core, 1620MHz Shader, 96 CUDA Cores, DVI, HDMI, VGA, PCIe 2.0,

EVGA GeForce GT 640 Single Slot 4GB GDDR3

900MHz Core, 384 CUDA Cores, 2 x DVI, mHDMI, PCIe 3.0,

ZOTAC GeForce GTX 650 Ti OC 2GB GDDR5

941MHz Core, 768 CUDA Cores, 2 x DVI, 2 x HDMI, PCIe 3.0

So does this mean that if you use a Sandybridge E i7 3820/3930 CPU (PCIe revision 2.00) on a Socket 2011 motherboard with PCIe 3.0 expansion slots then those revision 3.0 slots will not operate as PCIe 3.0 slots, but will actually operate at the fall back level of PCI 2.0 ?

If this is the case then it seems pointless installing a graphics card that is also a PCIe 3.0 card.

If this is not the case what actually happens ?????

My apologies if I appear to be clueless but can someone please clarify this for me?

Bryan (BPB)

Casio Exilim EX-Z77 Leica X1 Samsung i7
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