AMD Instinct MI455X
The AMD Instinct MI455X is a CDNA 5 GPU for frontier AI, designed for the AMD Helios rack-scale system.
- Vendor
- AMD
- Architecture
- CDNA 5
- Memory
- 432 GB HBM4
- Memory bandwidth (TB/s)
- 23.3 TB/s
- FP8 (TFLOPS)
- 20,100 TFLOPS
- FP4 (PFLOPS)
- 40.3 PFLOPS
- Form factor
- Enhanced Accelerator Module (EAM), direct liquid cooling, Helios rack
- Status
- Announced
The MI455X has 432 GB of HBM4 at 23.3 TB/s and 320 billion transistors on TSMC 2nm and 3nm. AMD launched it with the Instinct MI400 series at Advancing AI 2026 on July 23, 2026. It is an Enhanced Accelerator Module (EAM) with direct liquid cooling and UALink scale-out. AMD lists peak OCP FP8 at 20.1 PFLOPS and OCP MXFP4 at 40.3 PFLOPS.
- Memory (GB)
- 432 GB
- Precision note (sparse or dense)
- AMD lists peak OCP FP8 20.1 PFLOPS and OCP MXFP4 40.3 PFLOPS with no sparsity label (AMD gives separate structured-sparsity figures only for FP16, BF16 and INT8).
- Launch
- Launched July 23, 2026 (Advancing AI 2026)
- Vendor source
- amd.com
- Checked
Questions
How much memory does the AMD MI455X have?
The MI455X has 432 GB of HBM4 with 23.3 TB/s of memory bandwidth.
What is the MI455X’s FP8 and FP4 performance?
AMD lists peak OCP FP8 at 20.1 PFLOPS and OCP MXFP4 at 40.3 PFLOPS, with no sparsity label.
When was the AMD MI455X announced?
AMD launched it with the Instinct MI400 series at Advancing AI 2026 on July 23, 2026.
What is AMD Helios?
Helios is AMD’s rack-scale system that the MI455X is designed for, using Enhanced Accelerator Modules with direct liquid cooling.
Source
Every figure is taken from the vendor’s own datasheet, product page, technical documentation or announcement, linked on each chip with the date it was last checked. How we pick and check sources: editorial standards.