Scaling the Memory Wall: The Rise and Roadmap of HBM
… The additional area required to fit these TSVs is what makes HBM die sizes larger than their DDR equivalent: SK Hynix D1z DDR4 has a bit density of 0.296 Gb/mm 2 , 85% more dense than their HBM3 which is 0.16 Gb/mm 2 . …