Right now I have 2x4 gb stick of patriot viper extreme RAM. 1600 speed, 1.5v, but the timing on these is 11-11-11-28. I want to buy another 2x4 gb and the speed and the voltage are the same, but the timing is 10-10-10-27. Also the sticks I have right now are CL 11, while the ones i want to buy are CL 10. Can I mix these?