Question about clock ratio

[zzczzc20]

Dear all, In the standalone mode, there is a parameter called clock ratio. I want to know whether it uses the clock of memory or memory controller.

For example, if the CPU frequency is 2.8GHz, and I use DDR%-5600. If it is the clock of the memory it should be 1:1. If it is the clock of memory controller, the ratio should be 2:1, let us say the clock frequency of memory controller is 1.4GHz.