AMD's Instinct MI300 is shaping up to be an incredible chip with CPU and GPU cores and a hefty slab of high-speed memory brought together on the same processor, but details have remained slight. Now we've gathered some new details from an International Super Computing (ISC) 2023 presentation that outlines the coming two-exaflop El Capitan supercomputer that will be powered by the Instinct MI300. We also found other details in a keynote from AMD's CTO Mark Papermaster at ITF World 2023, a conference hosted by research giant imec (you can read our interview with Papermaster here). The El Capitan supercomputer is poised to be the fastest in the world when it powers on in late 2023, taking the leadership position from the AMD-powered Frontier. AMD's powerful Instinct MI300 will power the machine, and new details include a topology map of a MI300 installation, pictures of AMD's Austin MI300 lab, and a picture of the new blades that will be employed in the El Capitan supercomputer. We'll also cover some of the other new developments around the El Capitan deployment.
As a reminder, the Instinct MI300 is a data center APU that blends a total of 13 chiplets, many of them 3D-stacked, to create a single chip package with twenty-four Zen 4 CPU cores fused with a CDNA 3 graphics engine and eight stacks of HBM3 memory totaling 128GB. Overall the chip weighs in with 146 billion transistors, making it the largest chip AMD has pressed into production. The nine compute dies, a mix of 5nm CPUs and GPUs, are 3D-stacked atop four 6nm base dies that are active interposers that handle memory and I/O traffic, among other functions. Papermaster's ITF World keynote focused on AMD's "30x25" goal of increasing power efficiency by 30x by 2025, and how computing is now being gated by power efficiency as Moore’s Law slows. Key to that initiative is the Instinct MI300, and much of its gains come from the simplified system topology you see above. As you can see in the first slide, an Instinct MI250-powered node has separate CPUs and GPUs, with a single EPYC CPU in the middle to coordinate the workloads. In contrast, the Instinct MI300 contains a built-in 24-core fourth-gen EPYC Genoa processor inside the package, thus removing a standalone CPU from the equation. However, the same overall topology remains, sans the standalone CPU, enabling a fully-connected all-to-all topology with four elements. This type of connection allows all of the processors to speak to each other directly without another CPU or GPU serving as an intermediary to relay data to the other elements, thus reducing latency and variability. That's a potential pain point with the MI250 topology. The MI300 topology map also indicates that each chip has three connections, just as we saw with MI250. Papermaster's slides also refer to the active interposers that form the base dies as the 'fourth-gen infinity fabric base die." As you can see in the remainder of these slides, the MI300 has placed AMD on a clear path to exceeding its 30X25 efficiency goals while also outstripping the industry power trend. We also threw in a few pictures of the Instinct MI300 silicon we saw firsthand, but below we see how the MI300 looks inside an actual blade that will be installed in El Capitan.