Question DDR4 2133mhz ram runs at DRAM freq of 665 when its actually supposed to be 1066

I have attached a CPU-Z screenshot. My task manager shows that its a 2133mhz ddr4 ram but CPUZ shows its dram frequency as 665 (but occasionally changes to 1066 for a second and reverts back to 665 ). Can someone please help

screenshot - https://imageshack.com/i/po51oHrvp
Please post your system specs including Motherboard, CPU, and memory kit model. CPU-Z has most of that information on the other tabs.