What is HBM4 High Bandwidth Memory?

HBM4 is the next generation of High Bandwidth Memory, a stacked DRAM architecture that widens the memory interface and increases the number of stacked dies to push per-package bandwidth beyond earlier HBM generations. It typically pairs memory-maker DRAM dies with a separately fabricated logic base die, allowing chip designers to customize the base layer for a specific accelerator rather than using a generic memory controller interface.