RAM producers and sellers.

This is why I use Crucial.com so I can see what is compatible. You seem to have found a fit but here are a dozen other parameters PLUS another problem.

If you are mixing sticks of RAM you need to make sure they are all the same make and model to avoid problems that are too hard to figure out.

If you want to be completely sure, the seller and makers need to give you this assurance. They often do this with their return policy. If they don't allow returns, shop elsewhere.