hp pavilion 15ck0xx ram upgrade

[realz23]

i have this same question {I have an HP Pavilion 15 ck0xx Laptop. It has 8 GB DDR4-2400 MHz RAM (1 x 4 GB). I would like to add another 8 GB DDR4-2666 MHz RAM (1 x 8 GB) into the empty RAM slot on my laptop. Does the current mother board support both 2400 and 2666 MHz RAM simultaneously?} but to mine when i add the rams my pc isnt turning on 

[Paul_Tikkanen]

It's probably more of a compatibility problem than a different speed problem.

Your DDR4 2400 MHz memory chip is CL17 and the DDR4-2666 chip has to be CL19 in order for it to work with the DDR4-2400 chip.