# El Capitan: every supplier in the machine

Lawrence Livermore National Laboratory · US · system record on Compute Atlas: https://computeatlas.net/supercomputers/systems/el-capitan

## Specs

- **accelerator:** AMD Instinct MI300A APU, 4 per node (6 GPU dies with 228 compute units, 3 Zen 4 CPU dies with 24 cores, 4 I/O dies, 8 HBM3 stacks per package)
- **host cpu:** None separate: each MI300A carries 24 Zen 4 x86 cores (3 CCDs of 8 cores) on the same package
- **integrator:** HPE (HPE Cray EX; TOP500 lists the system as HPE Cray EX255a)
- **nodes:** 11,104 compute nodes in 87 HPE Cray EX ("Olympus") cabinets with 29 CDUs (LLNL Getting Started slides, March 2026); 4 MI300A per node
- **memory:** 512 GB HBM3 per node (4 x 128 GB, one pool shared by CPU and GPU dies; no separate DRAM), 5.3 TB/s peak bandwidth per APU
- **interconnect:** HPE Slingshot-11, dragonfly topology, 64-port 25.6 Tb/s switches, 4 x 200 Gb/s interfaces per node (100 GB/s injection)
- **storage:** Global Lustre file system, 401 PB and 2.6+ TB/s, on 42 E1000 storage racks; plus 696 HPE "Rabbit" near-node modules (21 PB, 31 TB/s) tiered to Lustre
- **cooling:** 100% fanless direct liquid cooling in the cabinets (HPE) with 29 CDUs; facility warm-water plant of six 3,000-ton cooling towers, 28,000 tons total, using ASHRAE W3 water with chillers largely avoided
- **power mw:** 29.68 MW (29,684.62 kW, power measurement level 2, TOP500 June 2026 list entry; identical on the November 2025 list)
- **rmax pflops:** 1,809.00 PFlop/s (TOP500 June 2026 list)
- **rpeak pflops:** 2,821.10 PFlop/s (TOP500 June 2026 list)
- **status note:** Dedicated at LLNL on 2025-01-09; first benchmarked on the November 2024 TOP500 list; TOP500 gives installation year 2024; first exascale system built for NNSA

Unmarked companies come from the operator's or vendor's own pages (llnl.gov, hpc.llnl.gov, hpe.com); reported companies come from named trade press whose article body was read in full, not just the headline. This is a map of who plays where, not a confirmed bill of materials: LLNL documents (hpc.llnl.gov hardware and file-system pages, LLNL Getting Started slides, S&TR December 2024, llnl.gov news), HPE's November 2024 El Capitan press release, the TOP500 system entry, and named trade press, researched 2026-10-02

## Lines

1. System design and cabinets (HPE Cray EX, 87 liquid-cooled cabinets, built with AMD and Red Hat)
   - parts: Rack-scale systems (4.01)
   - companies: HPE (integrator and Cray EX cabinet supplier)
   - sources: https://www.llnl.gov/article/52336/llnl-dedicates-el-capitan-ushering-new-era-supercomputing-national-security https://hpc.llnl.gov/sites/default/files/2026-03/Getting-started-March-2026.pdf
2. Compute blade and node (HPE Cray EX255a; a blade holds two nodes, a node holds 4 MI300A APUs)
   - parts: GPU baseboards & compute trays (4.03)
   - companies: HPE (EX255a accelerator blade); AMD (MI300A APUs on the blade)
   - not confirmed: board, connector and voltage-regulator suppliers (HPE does not itemise the blade)
   - sources: https://hpc.llnl.gov/documentation/user-guides/using-el-capitan-systems/hardware-overview https://str.llnl.gov/str-december-2024/introducing-el-capitan https://www.top500.org/system/180307/
3. AMD Instinct MI300A APU (CPU, GPU, cache and HBM3 in one package; 24 Zen 4 cores, 228 CDNA 3 compute units, 128 GB HBM3)
   - parts: Merchant GPUs / accelerators (1.01); Server CPUs (1.05)
   - companies: AMD
   - not confirmed: HBM3 stack supplier (LLNL, HPE and AMD materials read do not name one; trade press on the wider MI300 family is not specific to the MI300A)
   - sources: https://hpc.llnl.gov/documentation/user-guides/using-el-capitan-systems/hardware-overview https://str.llnl.gov/str-december-2024/introducing-el-capitan
4. MI300A dies fabricated by TSMC (N5 compute dies, N6 I/O and cache dies) and joined with TSMC SoIC and CoWoS packaging
   - parts: Leading-edge foundry (1.09); 2.5D/3D advanced packaging (1.11)
   - companies: TSMC* (foundry for all MI300A logic dies; SoIC and CoWoS integration)
   - sources: https://www.nextplatform.com/hpc/2024/11/18/el-capitan-supercomputer-blazes-the-trail-for-converged-cpu-gpu-compute/1646378 https://spectrum.ieee.org/amd-mi300
5. Slingshot-11 fabric (HPE Rosetta switches, dragonfly topology, 64 ports at 200 Gb/s)
   - parts: Scale-out switch ASICs (3.02); Switch systems & white-box ODMs (3.03)
   - companies: HPE
   - not confirmed: cable and optics suppliers (copper and optical links are not itemised in any source read)
   - sources: https://hpc.llnl.gov/documentation/user-guides/using-el-capitan-systems/hardware-overview https://www.hpe.com/us/en/newsroom/press-release/2024/11/hewlett-packard-enterprise-delivers-worlds-fastest-direct-liquid-cooled-exascale-supercomputer-el-capitan-for-lawrence-livermore-national-laboratory.html
6. Slingshot-11 network interfaces (4 x 200 Gb/s per node, one per APU, on PCIe 5.0 x16)
   - parts: NICs / SuperNICs (1.06)
   - companies: HPE
   - sources: https://hpc.llnl.gov/documentation/user-guides/using-el-capitan-systems/hardware-overview
7. Rabbit near-node storage (4U module: 16 SSDs plus one AMD EPYC storage processor, two per cabinet, each wired to 16 compute nodes)
   - parts: AI storage systems (2.10); Server CPUs (1.05)
   - companies: HPE (co-developed the Rabbit with LLNL); AMD (EPYC storage processor in each Rabbit)
   - not confirmed: SSD maker (LLNL names the drive count per module but not the drive vendor)
   - sources: https://hpc.llnl.gov/documentation/user-guides/using-el-capitan-systems/file-systems-rabbits
8. Global Lustre file system (401 PB, 2.6+ TB/s; 42 E1000 storage racks, HPE Cray ClusterStor E1000 per 2019 reporting)
   - parts: AI storage systems (2.10)
   - companies: HPE* (HPE (Cray) ClusterStor E1000 named as El Capitan's external storage in 2019; LLNL's current slides list "42 E1000" racks)
   - not confirmed: drive makers (the E1000 uses NVMe SSDs and disk drives per the 2019 reporting; no drive vendor named for El Capitan); whether the delivered E1000 racks match the 2019 plan beyond the product name (LLNL's slides give "E1000" and capacity but not the model line)
   - sources: https://hpc.llnl.gov/sites/default/files/2026-03/Getting-started-March-2026.pdf https://blocksandfiles.com/2019/10/31/cray-clusterstor-e100/
9. In-cabinet liquid cooling (100% fanless direct liquid cooling, 29 coolant distribution units)
   - parts: Direct-to-chip cold plates (5.01); Coolant distribution units (5.05)
   - companies: HPE (fanless direct liquid cooling architecture)
   - not confirmed: cold plate, manifold, quick-disconnect and CDU component suppliers (HPE does not itemise them)
   - sources: https://www.hpe.com/us/en/newsroom/press-release/2024/11/hewlett-packard-enterprise-delivers-worlds-fastest-direct-liquid-cooled-exascale-supercomputer-el-capitan-for-lawrence-livermore-national-laboratory.html

* reported: named trade press or analyst reporting rather than the operator or vendor.

## What could not be confirmed

No source read names the maker of the HBM3 stacks, the Rabbit SSDs, the Lustre drives, the cabinet cold plates or coolant distribution units, or the Slingshot cables and optics, and LLNL does not name the manufacturers of the cooling towers, the 115 kV substation transformers or the switchgear. Cabinet, node, power and peak-performance figures also differ between LLNL documents and TOP500, as noted in the specs. The facility side, per LLNL, is a 115 kV feed into two 40 MW substation transformers (85 MW of building capacity) and a warm-water cooling plant of six 3,000-ton towers; no line is given to either here because LLNL names no equipment maker for them.