The memory controller nowadays locates on the processor; therefore, the RAM speed is limited to what the memory controller has been designed to support. If using 1600 MHz it might be expected to see the processor downgrading the speed to what it supports: 1066/1333 MHz
Thank you. Unfortunately, this is my big mistake by selecting a processor. I did not read the specification(s) of this processor regarding on the memory before buying one.
I guess I will have to recover the limit of the processor by upgrading the memory sizes.