ram is this ram compatible with the ram I have now?

[nandebro]

Hello, I was wondering if this ram is compatible with this ram that I already have in my system? Amazon doesn't seem to have the one I bought in stock (and I'm not too sure if they even make them anymore), I have a gift card and was looking to spend it on ram so I could upgrade from 8gb to 16gb since the gift card would cover the cost.

I know that the older ram is 2133mhz cl14 and the newer one is 2666mhz with cl16, and that it would underclock to match the ones I have right now. And from what I read the cl14 would run at the cl16 speeds? So I'm just confused if it would even be compatible since it seems one each one would underclock for different reasons (I honestly didn't even know what the cl speeds were until I was looking into it just a bit ago lol). And would I be missing out on that much speed if they are compatible? So is it even worth it or should I just sell the ram in my system right now and just get two 2x4gb kits of the newer ram instead... I'm so confused!!!!

 

My motherboard is a ASRock Z170A-X1/3.1 ATX LGA1151 Motherboard in case ya'll needed to know

 

any help would be appreciated & thanks for reading!