Samsung RAM compatibility and serial number meaning

Aug 1, 2018
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I have an hp 450 g1 with 4gb ddr3 memory. I would like to upgrade as my laptop has a spare slot, but am unsure if the memory I found is fully compatible with the memory I already have in my laptop.

Memory already in laptop - https://amzn.to/2OwSCKW
S/N - M471B5173DB0-YK0

Memory I want to upgrade to - https://amzn.to/2LHY0Nz
S/N - M471B1G73DB0-YK0

Upgrade option 2 - https://amzn.to/2vav3Q1
S/N - M471B5273DH0-CK0

I noticed the last three digits in each serial number are the same in the original 4gb stick and the 8gb stick. Does this mean they are compatible? Does this mean the option 2 stick isn't compatible? Do I have to buy a second module of the more expensive 4gb ram I already have?


*** I don't need the extra 8gb of RAM I only need an extra 4gb. I found a 4gb module with the same last three digits. Would that work as well?

More practical option for my needs - https://amzn.to/2AC3W5F
S/N - M471B5173EB0-YK0



Thank you again for your help:)