5.5 Steamroller: An x86-64 core implemented in 28nm bulk CMOS

The AMD two-core x86-64 CPU module, codenamed “Steamroller”, contains 236 million transistors implemented in 28nm high-κ metal gate (HKMG) bulk CMOS using 12 levels of metal. It is designed to operate from 0.8 to 1.45V. The CPU module occupies 29.47 mm
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, which includes two independent integer cores, two instruction decode units and shared instruction fetch, floating-point, and 2MB 16-way L2 cache units (Fig. 5.5.7). Along with the second instruction decode unit, this design includes a larger shared 96KB 3-way instruction cache and a 10KB L2 branch target buffer for improved single-threaded performance and multi-threaded throughput compared to a previous 32nm AMD x86-64 CPU codenamed “Bulldozer” [1].