AMD Radeon Instinct MI300A: A Deep Dive into its Massive APU Architecture

The AMD Radeon Instinct MI300A is a colossal APU integrating 24 Zen 4 cores and 228 CDNA3 compute units. This article delves into its massive Infinity Fabric interconnect, highlighting its high-bandwidth, low-latency characteristics and efficient CPU-GPU data sharing. While its high-bandwidth memory subsystem excels for the GPU, it impacts CPU latency, resulting in single-threaded integer performance comparable to the Ryzen 9 3950X from years ago. Despite this, MI300A has achieved significant success in supercomputing, notably powering LLNL's El Capitan system and topping the TOP500 list.