Dell Memory 4GB RDIMM, 2133MT/s, Single Rank, x8 Data Width,CusKit 370-ABUM
Single Rank vs Dual Rank RAM: Differences & Performance Impact
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