I recently tried memory sdram from Hynix 8GB 1X8GB PC3-12800 2RX8 DDR3-1600MHZ SDRAM ECC Unbuffered 204-Pin Sodimm from allhdd,
https://www.allhdd.com/memory-ram/ddr-sdram/ (guys im not recommending this to you, do your due diligence and make your own choices)
I think while there is a little difference in configuration, as I am using a DDR3, though its 8GB DDR, but I didn't know Hynix is a decent ddr sdram option.
Anyways near similar choices. Hope to upgrade soon with DDR4