IBM zEnterprise 196 microprocessor and cache subsystem

microprocessor and cache subsystem F. Busaba M. A. Blake B. Curran M. Fee C. Jacobi P.-K. Mak B. R. Prasky C. R. Walters The IBM zEnterpriseA 196 (z196) system, announced in the second quarter of 2010, is the latest generation of the IBM System zA mainframe. The system is designed with a new microprocessor and memory subsystems, which distinguishes it from its z10A predecessor. The system has up to 40% improvement in performance for traditional z/OSA workloads and carries up to 60% more capacity when compared with its z10 predecessor. The memory subsystem has four levels of cache hierarchy (L1 through L4) and constructs the L3 and L4 caches with embedded DRAM silicon technology, which achieves approximately three times the cache density over traditional static RAM technology. The microprocessor has 50% more decode and dispatch bandwidth when compared with the z10 microprocessor, as well as an out-of-order design that can issue and execute up to five instructions every single cycle. The microprocessor has an advanced branch prediction structure and employs enhanced store queue management algorithms. At the date of product announcement, the microprocessor was the fastest complex-instruction-set computing processor in the industry, running at a sustained 5.2 GHz, executing approximately 1,100 instructions, 220 of which are cracked into reduced-instruction-set computing-type operations, to achieve large performance gains in legacy online transaction processing and compute-intensive workloads.