Bank-Group Level Parallelism

DDR4 SDRAM introduced a new hierarchy in DRAM organization: bank-group (BG). The main purpose of BG is to increase I/O bandwidth without growing DRAM-internal bus-width. We, however, found that other benefits can be derived from the new hierarchy. To achieve the benefits, we propose a new DRAM architecture using the BG-hierarchy, leading to a creation of BG-Level Parallelism (BGLP). By exploiting BGLP, the overall parallelism grows in DRAM operations. We also argue that BGLP is a feasible solution in the cost-sensitive DRAM industry because the additional cost is negligible and only cost-insensitive area needs to be modified.