Explain PCIe differences and help me choose a Z68 MB


I want to buy a Z68 MB for my i5 2500K. The reason i want a Z68 board is that i want to overclock and I also want to initially use onboard graphics.

Eventually I want to use dual HD 6950 in crossfire.

I'm getting a bit confused about PCIe 3.0 and the lanes thing..

It looks like PCIe 3.0 requires the Ivy Bridge CPUs. I don't know if it's actually useful for current graphics cards or cards in the near future.

From what i understand even the best motherboards only have x16 PCIe when you put in one graphics card. When you put in a second graphics card then that x16 is reduce to x8 for each card. Is this fine? Will a HD6950 max out x16 lanes? Will two HD6950s be maxing out their allocated x8 lanes?

If they do, then is this where PCIe 3.0 comes in? In that case, i'd need to update to Ivy Bridge then update my graphics cards to support PCIe 3.0?

Could someone please tell me if i i'm understanding things alright?

Now i need to buy a MB. I don't have a huge amount of choice so have narrowed it down to these contenders:

ASRock Z68 Extreme4
ASRock Z68 Pro3
Asus P8Z68-V
Asus P8Z68-V LE
Asus P8Z68-V LX
Gigabyte GA-Z68X-UD3H-B3
Gigabyte GA-Z68XP-UD3
Gigabyte GA-Z68X-UD3R-B3
Gigabyte GA-Z68XP-D3
Gigabyte GA-Z68A-D3H-B3

It looks to me like the MSI is the best of this bunch. It has support for PCIe 3.0 when it comes out as well as USB3 etc.

What would you guys suggest?

3 answers Last reply
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  1. PCIe 3.0 is nothing that we will have to worry about in the near future. There is still a lot of people running current generation cards in version 1.x slots just fine.
    My choice http://www.newegg.com/Product/Product.aspx?Item=N82E16813128512
  2. ^ while that is true, the new gen z68's with Ivy Bridge and PCIE-3 support arent any more expensive, so why not just get them. Many old pcie 1.x boards dont work with pcie 2.1 cards so if you have a 3.0 ready motherboard, at least you may have some further compatability. I wouldnt buy that crappy gigabyte board with no UEFI, no IB support.
  3. Thanks for the replies.

    My plan is to get either the MSI or Asrock gen 3 boards. None of which are in that list i gave in my first post because they're not out where i live just yet.

    I think the benefit of having the PCIe 3.0 support and IB support is worth waiting for. Even if the benefit is currently non-existant - who knows what I might need in the future.
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