Providing memory bandwidth compression using multiple last-level cache (LLC) lines in a central processing unit (CPU)-based system

Providing memory bandwidth compression using multiple last-level cache (LLC) lines in a central processing unit (CPU)-based system is disclosed. In some aspects, a compressed memory controller (CMC) provides an LLC comprising multiple LLC lines, each providing a plurality of sub-lines the same size as a system cache line. The contents of the system cache line(s) stored within a single LLC line are compressed and stored in system memory within the memory sub-line region corresponding to the LLC line. A master table stores information indicating how the compressed data for an LLC line is stored in system memory by storing an offset value and a length value for each sub-line within each LLC line. By compressing multiple system cache lines together and storing compressed data in a space normally allocated to multiple uncompressed system lines, the CMC enables compression sizes to be smaller than the memory read/write granularity of the system memory.