I am building a computer and have found two virtually identical (in my view) options for RAM:
Option 1: "G.SKILL F3-10666CL9D-8GBRL Ripjaws 8GB 2X4GB DDR3-1333 CL9-9-9-24 240PIN DIMM Memory"
Option 2: "G.SKILL Ripjaws X F3-10666CL9D-8GBXL 8GB 2X4GB DDR3-1333 CL9-9-9-24 Memory"
My motherboard is an Intel BOXDP67DEB3.
What's the difference between the two options?