As for the difference in the board specs, ask MSI, I don't think anyone here can definitively tell you what the differences are.
The specs I was referring to are the JEDEC DDR3 memory specification that states a maximum voltage of 1.575, The memory you listed is 1.6v, and the actual specification for DDR3 calls for 1.5v. You should stick to 1.5v memory unless you like your system to crash/BSOD.
As for the differences between CL9 and CL10, here is a couple links for you to do some research
I will boil down a little bit for you though. A 10% lower CL = 10% faster access time to ram. Lower CL can be of greater benefit than increased frequency. A higher frequency increases memory throughput (how much data can be transferred in a period of time), but also increases latency (time it takes to access the ram). Unless you are moving massive amounts of streamed data on a regular basis (file servers, virtual desktop servers etc..) you will have greater benefit from tighter timings than higher frequency.http://en.wikipedia.org/wiki/Memory_timingshttp://en.wikipedia.org/wiki/DDR3_SDRAM