More recently I built a watercooled i7-4960X, with an Asus X79-Deluxe motherboard, and 32 gig of G.Skill 2400Mhz memory.
You have to be careful with memory speed, the higher Mhz doesn't always mean it will be faster if the CL and other timings are slow. I actually made a spreadsheet at the time to compare speeds with prices etc. the 2400 was a good combination at the time. You also have to turn that on in the BIOS (XMP profiles) to get the memory to run at that speed (most motherboards you seem ot have to turn it on).