Here's my question. I know from reading that EVGA is a good manufacturer of boards, so i would really like to consider them for my build. But certainly their motherboards don't JUST support 2600+ memory, right? Am i missing something?
1- You won't see any difference between 2000 or 2600 and 1600, because the CL of the 2000 and 2600 is CL9 or CL10 that is very very slow for DDR3, so, IMO buy a RAM and buy a RAM with that speed is a wasted of money.
2- The Gigabyte mobo of your 2nd link support Crossfire at x8 that is good, but when you use Crossfire on that mobo, you USB 3.0 is downgrade to USB 2.0
3- IMO the ASUS P7P55D-E Pro is the best options for you.
I would go with the Gigabyte board over the EVGA board. The EVGA will support RAM less than 2600, so that isn't an issue. The difference is you are getting better features on the Gigabyte for a little more money!
Edit: I second the ASUS P7P55D-E Pro motherboard for under $190!!
Gigabyte’s P55A-UD4P cuts costs by using the processor’s PCIe 2.0 connections to host its high-bandwidth controllers. Two of the primary graphics card’s 16 PCIe lanes supply its USB 3.0 and SATA 6.0 Gb/s controllers, and Gigabyte disables six more lanes to make the upper slot an effective x8 interface. The USB 3.0 and SATA 6.0 Gb/s controllers revert to the chipset’s 2.5 GT/s lanes whenever two graphics cards are installed, to preserve the x8 transfers each graphics card needs for optimal CrossFire or SLI performance.
Thus, users with a single graphics card must sacrifice half of its peak bandwidth to enable 5.0 Gb transfers to the USB 3.0 and SATA 6.0 Gb/s controllers, while those with two cards must live with 2.5 Gb/s bandwidth limits on USB 3.0 and SATA 6.0 Gb/s controllers. Neither of these sacrifices is huge or even noticeable on most of today’s hardware, yet anyone trying to future-proof their system could be left cold.