A Case for Intelligent RAM: IRAM

David Patterson, Thomas Anderson, Neal Cardwell, Richard Fromm, Kimberly  Keeton, Christoforos Kozyrakis, Randi Thomas, Katherine Yelick  A Case for Intelligent RAM: IRAM. IEEE Micro, vol 17, no. 2, March/April 1997, pages 34 - 44.



Two trends call into question the current practice of microprocessors and DRAMs being fabricated as different chips on different fab lines: 1) the gap between processor and DRAM speed is growing at 50% per year; and 2) the size and organization of memory on a single DRAM chip is becoming awkward to use in a system, yet size is growing at 60% per year. Intelligent RAM, or IRAM, merges processing and memory into a single chip to lower memory latency, increase memory bandwidth, and improve energy efficiency as well as to allow more flexible selection of memory size and organization. In addition, IRAM promises savings in power and board area. We review the state of microprocessors and DRAMs today, explore some of the opportunities and challenges for IRAMs, and finally estimate performance and energy efficiency of three IRAM designs.