Question Pairing 2400 MHz RAM with pre-installed 2666 MHz

[danish17]

Hi.
I am currently ruuning a Lenovo Legion Y530 with Core i5 8300H and 8GB of pre-installed 2666MHz SODIMM memory. My laptop has a free memory slot for RAM upgrade and I want to install a 16GB module.

My question is:
Can I pair the pre-installed 2666MHz RAM with a 16GB 2400MHz one? Will it cause any issue?

 

[Fix_that_Glitch]

The memory it supports is 2666mhz. Three things can happen, 1. They don't work together because they are not from same package and different speed, and maker. 2. They work together but revert to the slower speed of the 2400mhz. 3. They will work together sometimes and cause random shut downs.