40 years ago, IBM’s DRAM breakthrough ushered in the megabit memory era — a major leap beyond the 64-kilobit chips common at the time

IBM became the first computer company to use 1-megabit DRAM in its 3090 mainframes, ushering in the megabit memory era.

The move marked a major leap from 64-kilobit and 256-kilobit chips, highlighting a sharp rise in memory density.

Japanese rivals including Fujitsu, Hitachi, Mitsubishi, NEC, and Toshiba were preparing similar chips for mass production.

The breakthrough helped pave the way for higher-capacity memory modules used in PCs and other hardware, including 30-pin SIMMs.