Question Want to know if two different types of DDR4 RAM are compatible

[LeGossler]

I recently bought a laptop and it came with 8GB ram. 1 x SK hynix 8GB 1Rx8 PC4-2400T-SA1-11.

As I'm working with very large data sets, the ram was not sufficient and I decided to get it upgraded to the maximum my laptop can take, which is 16GB (8GB x 2).

I took it to the store and they installed two new ram cards. 2 x G.Skill Ripjaws F4 2400C16S-8GRS.

When I asked why they need to install two new 8GB ram cards instead of just adding one they said that it is because the two different brands could cause issues so they want the two ram cards to be identical. I don't know why, but the sales person who answered my question did not sound convincing at all, so I thought this might be him trying to cover up the fact that they tricked me into buying two cards when I only needed one additional card.

I hope I am wrong about this but I just need to make sure.

If there is anyone who can confirm that they were telling the truth, I would really appreciate it.
Thanks!

 

[ConanLock]

They are correct in saying that mismatched RAM can cause issues. Some systems and RAM sticks are more sensitive to this than others. However, to avoid issues, it is best to always get matching sticks. You see, in addition to speed and capacity, RAM also varies according to its timing. You will have to look into what this is, as it can get quite complex, but basically if these don't match then they will respond to the data that the motherboard is sending at different speeds, and you can probably guess what issues this has potential to cause.