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The PCIe standards are backward compatible so a PCIe3.0 slot that does not have an Ivy Bridge processor will simply act as a PCIe 2.0 slot. Since most current graphics cards are unable to saturate the bandwidth of PCIe 2.0, there shouldn't even be any problems there. The motherboard notation is simply reminding you (or making you aware) that you will not get PCIe 3.0 through-put speeds from your graphics card (even if it has that capability). Nothing really to worry about.
That's what I was thinking. Thank you my friend.