What is the difference between single rank and dual rank memory? - Quora
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
Does using different sizes of RAM in a dual channel reduce performance? - Quora
16GB (4x4GB) Memory RAM for IBM Intellistation Z Pro (6223-xxx) Dual RANK B48 | eBay
PE129859 Edge Memory 64MB EDO Non-ECC Unbuffered 3.3V SODIMM 144-pin Dual bank Memory