An energy efficient cache design using Spin Torque Transfer (STT) RAM

The on-chip memory is a dominant source of power and energy consumption in modern and future processors. This paper explores the use of a new emerging non-volatile memory technology as a replacement for SRAM based lower level caches — Spin Torque Transfer(STT) RAM. While STTRAM achieves a reduction in leakage energy of 90% compared to SRAM, the dynamic energy for a write operation is 2X that of SRAM. Consequently, we propose additional microarchitectural optimizations to reduce overall dynamic energy which achieve an average reduction in dynamic energy over the base case of 30% with a range of 16% to 60% across 10 benchmarks.