Beware of the single rank x16 RAM kits sneaked in some laptop models! The 1Rx16 modules have significantly lower bandwidth compared to the 1Rx8 variants - NotebookCheck.net News
What is the difference between the RAM labeled '1Rx8 PC3L-12800S-11-13-B4' (inside the laptop) and '2Rx8 PC3-12800S-11-11-F3' (planning to buy)? - Quora
Solved: RAM for laptop - HP Support Community - 7355494
SK HYNIX HMA851S6CJR6N 4GB 1RX16 DDR4 SO-DIMM PC4-19200 2400MHZ Laptop Memory at Amazon.com