Wait wait wait wait wait.
The Prelude is PCI, yes? I don't believe there's going to be an open PCI slot (there's only one) on that board with two dual-slot video cards installed. I'd cancel the Prelude order quick.
Silent,
you can put one card in a blue PCI-E 2.0 slot and another in the white x16 1.1 with no issues or performance loss (despite what the MSI manual says.) I do this with my two GTXes and run my PCI X-Fi. No problems, no worries
