Newly purchased Late 2015 iMac. Put in "Corsair Mac Memory - DDR3L - 16 GB: 2 x 8 GB - SO DIMM 204-pin - 1866 MHz / PC3L-14900 - CL11 - 1.35 V" that was branded as "Apple memory". Forgot to look in "About this Mac" before the RAM update, but looking now it says that all my four RAM slots have 1600 MHz memory. Does macOS often misrepresent RAM speed, or should I worry? I know 1600 vs 1866 is not a big difference in terms of speed, but I still want to obtain 1866 speeds if that's what I have.