Want the lowest CL you can get at the spec freq you go with say (2133/9, 2400/10) thet'll allow some OC room, the RJ X you're looking at should go 2400 w/ CL10, have used a number of those sets
well my other option unfortunately is a 1866 cl10's, based on what is in stock, I want to get the cl9's at 1866 but they are also back ordered...both modules are at 1.5v though which stays within the mobo specs
G.SKILL Ripjaws X Series 16GB (2x8GB) DDR3 1866MHz CL10 Dual Channel Kit (F3-14900CL10D-16GBXL)
I know the sweet spot for haswell seems to be 1600mhz anyway?
Haswell, is great w/ DRAM, far better than SB or IB, I've got a little over 20 Haswell builds and 1866 has been the lowest I've built (2), 2133 is the preferred and the higher end folks mainly go 2400-2800, I've got 2666 in mine