Wide I/O or LPDDR? Exploration and analysis of performance, power and temperature trade-offs of emerging DRAM technologies in embedded MPSoCs

Abstract

Wide I/O, the recent JEDEC DRAM standard, has created an opportunity for architects to overcome the "memory wall" challenge. 2.5D/3D integration enables Wide-IO to deliver high memory bandwidth and low latency for mobile applications. On the other hand, LPDDR3 was introduced to mainly address the power budget challenge in embedded MPSoCs. Employing either Wide I/O or LPDDR3 leads to different power, performance and thermal behavior of the system that necessitates a thorough analysis of both technologies. In this paper, we present a comprehensive analysis of the latency, performance, power and thermal behavior of these two emerging DRAM technologies in embedded MPSoCs. We conduct a comprehensive study to understand the impact of core count, core micro-architecture, and core-memory integration technology on the trade-offs that these two memory technologies offer. We show that while stacked Wide I/O outperforms LPDDR3 by as much as 7%, it increases the power consumption by 14%. To improve the power efficiency, we evaluate stacked LPDDR3, a DRAM design that is as high performance as Wide I/O - yet it is as power efficient as LPDDR3.