Milan (microprocessor)

Milan (microprocessor)
Name	Milan
Designer	Advanced Micro Devices
Bits	64-bit
Introduced	2021
Design	Zen 3
Cores	Up to 64
Socket	Socket SP3
Predecessor	Rome
Successor	Genoa

Milan (microprocessor). Milan is the codename for a family of server and workstation central processing units designed by Advanced Micro Devices (AMD) and launched in March 2021. Based on the company's Zen 3 microarchitecture, it succeeded the Rome platform and was manufactured using an advanced 7 nm process from TSMC. The processors were designed to offer significant performance improvements in enterprise, high-performance computing, and cloud computing workloads, competing directly with Intel's contemporary Xeon Scalable processors.

Overview

The Milan family, officially branded as the third generation of AMD EPYC processors, represented a major evolutionary step within the existing Socket SP3 infrastructure. This allowed for platform compatibility with previous-generation Rome and Naples servers, providing an upgrade path for data center customers. The launch was a key part of Advanced Micro Devices' strategy to increase its market share in the lucrative server segment against rival Intel. Key partners for system integration included Hewlett Packard Enterprise, Dell Technologies, Lenovo, and Super Micro Computer.

Architecture

Milan is built on the Zen 3 core design, which introduced a unified 32-megabyte L3 cache complex for each 8-core Core Complex (CCX), a major change from the split cache in the prior Zen 2 architecture used in Rome. This redesign reduced memory latency and improved core-to-core communication. The processors utilize a Chiplet design, with up to nine 7 nm dies: eight core complex dies (CCDs) and one central I/O die (IOD) built on a more mature process node. The IOD manages connectivity, including support for PCI Express 4.0 and memory interfaces.

Performance and features

Milan offered a substantial IPC (instructions per cycle) uplift, with Advanced Micro Devices claiming a 19% average generational improvement over Rome. This translated to leading performance in a wide range of benchmarks for server applications, including SPECint, database workloads, and high-performance computing simulations. Key features included support for up to 4 terabytes of DDR4 memory across eight channels, 128 lanes of PCI Express 4.0, and advanced security features like AMD Secure Encrypted Virtualization (SEV). These capabilities made it highly competitive against Intel's Ice Lake-SP Xeon processors.

Product lineup

The Milan lineup spanned from 8-core to 64-core models, segmented for different market needs. The EPYC 7003 series included standard power parts (e.g., EPYC 7763), optimized parts for cloud density (EPYC 75F3), and frequency-optimized models for tasks like financial modeling. AMD also introduced the EPYC 7003X series with 3D Vertical Cache technology, stacking additional L3 cache on select models like the EPYC 7373X to boost performance in targeted workloads like computational fluid dynamics. This stacking technology was a precursor to its broader use in later products like Raphael.

Manufacturing process

All core compute dies for Milan were fabricated by TSMC using its enhanced 7 nm process node, often referred to as N7. This process provided a density and power efficiency advantage over the competing Intel 10 nm node used for contemporary Xeon chips. The I/O die continued to be manufactured on a older GlobalFoundries 14 nm or 12 nm process, a cost-effective choice for the less density-sensitive component. The chiplet approach allowed Advanced Micro Devices to maximize yields and mix dies from different wafers.

Market reception and impact

Milan was met with strong critical acclaim from industry analysts and publications like AnandTech and ServeTheHome, which highlighted its performance leadership and efficiency. It secured major design wins with cloud providers such as Google Cloud, Microsoft Azure, and Amazon Web Services, as well as in prestigious high-performance computing systems like the Frontier supercomputer at Oak Ridge National Laboratory. The success of Milan significantly eroded Intel's dominance in the server market, with Advanced Micro Devices achieving its highest server CPU market share in decades and setting the stage for its next-generation Genoa platform.

Category:Advanced Micro Devices microprocessors Category:Server microprocessors Category:X86 microprocessors