First..
Big NO to that mobo..
MSI 970A-G46 won't run FX8350...crappy vrm, no heatsink for power phase..well, this one is very easy to burn..
it's just limited to fx6300 class cpu..
second..
get G.Skill F3-14900CL10S-8GBXL..
because 970/990fx chipset support 1866Mhz natively. and it'll be faster than G.Skill F3-12800CL9D-8GBXL..
But..
If you only have single stick G.Skill F3-14900CL10S-8GBXL, then go with 2xG.Skill F3-12800CL9D-8GBXL.
Because G.Skill F3-12800CL9D-8GBXL in dual channel will a lot faster than G.Skill F3-14900CL10S-8GBXL in single channel..