R&D: Performance Analysis of 3D-Triple-Level Cell and 2D-Multi-Level Cell NAND Flash Hybrid SSD

Japanese Journal of Applied Physics, Volume 57, Number 4S has published an article written by Yukiya Sakaki, Tomoaki Yamada, Chihiro Matsui, Yusuke Yamaga and Ken Takeuchi , Chuo University, Bunkyo, Tokyo 112-8551, Japan

Abstract :  “In order to improve performance of solid-state drives (SSDs), hybrid SSDs have been proposed. Hybrid SSDs consist of more than two types of NAND flash memories or NAND flash memories and storage-class memories (SCMs). However, the cost of hybrid SSDs adopting SCMs is more expensive than that of NAND flash only SSDs because of the high bit cost of SCMs. This paper proposes unique hybrid SSDs with two-dimensional (2D) horizontal multi-level cell (MLC)/three-dimensional (3D) vertical triple-level cell (TLC) NAND flash memories to achieve higher cost-performance. The 2D-MLC/3D-TLC hybrid SSD achieves up to 31% higher performance than the conventional 2D-MLC/2D-TLC hybrid SSD. The factors of different performance between the proposed hybrid SSD and the conventional hybrid SSD are analyzed by changing its block size, read/write/erase latencies, and write unit of 3D-TLC NAND flash memory, by means of a transaction-level modeling simulator. “