XMP reading on F3-12800CL9-4GBRL

[xtoob]

MSI NF980-G65
Phenom II 965 BE
Ripjaw F3-12800CL9 2x2gb and 2x4gb

I got the 2-2gb modules in a package with the mother board, and before knowing about the AMD memory limitations bought the 2-4gb modules for a total of 12gb. I'm trying to learn all the settings before I jump into OC'ing, but I'm stumped by what is showing up for the CPU-Z XMP readings on the 4gb modules. I have the 4gbs in slots 1+2, and the 2gbs in slots 3+4. I haven't noticed any problems but I haven't pushed anything yet either. The 4.5v for the XMP setting on the 4gb modules makes me nervous about loading XMP. Any thoughts about the difference between the 4gb and 2gb modules?

[GSKILL TECH]

What is the 4.5v? Both kits will operate on same memory specifications, but 4 modules may need additional voltage to the NB Voltage.

Thank you
GSKILL TECH