Hi. I Have the following memory : 1600mhz CL9 4GB 2x2, now I want to upgrade and I can get 1600mhz CL9 8GB 4x2 to make it a total of 12GB. But I see theirs 2133mhz CL10 modules as well both cost the same price. Should I rather go for faster 8GB ram and if see its not enough I can still let it run at a lower speed 1600mhz CL9 in future. What do you guys recommend ?