AMD Instinct MI325X vs AMD Radeon Instinct MI300A Comparison

Head-to-Head Benchmarks

The database contains no recorded benchmark scores for either the AMD Instinct MI325X or the AMD Radeon Instinct MI300A. Both entries show an average benchmark score of zero, and the head-to-head benchmark array is empty. Consequently, there are no measured performance deltas, no percentile rankings beyond the identical 50th percentile against all GPUs, and no rival comparison data available for these two accelerators.

The absence of benchmark results does not diminish the value of the recorded specifications. What the database does provide is a complete set of hardware parameters for both parts, and those parameters reveal a clear performance envelope for each accelerator. The MI325X and MI300A share the same silicon foundation: both use the Aqua Vanjaram chip, built on TSMC 5 nm process technology, with 153,000 million transistors on a 1017 mm² die, yielding a transistor density of 150.4M per mm². Both parts also carry identical shader configurations: 19,456 shading units, 1,216 texture mapping units, and zero raster operation pipelines. The pixel rate for each is 0 MPixel/s, and the texture rate is 2,553.6 GTexel/s for both. The FP32 compute throughput is also identical at 81.72 TFLOPS.

Those shared specifications mean that the raw compute engines are the same. The differences that do exist are concentrated in memory configuration, memory clock speeds, FP16 throughput, thermal design power, and release timing. These differences are substantial enough to define distinct application profiles.

Where Each One Wins

The MI325X takes the lead in memory capacity and memory technology. It is equipped with 256 GB of HBM3e memory, compared to the MI300A's 192 GB of HBM3. The larger capacity directly benefits workloads where model weights, activation maps, or dataset batches must reside on the accelerator itself. For large language model inference or training with very large batch sizes, the extra 64 GB can determine whether a model fits entirely on a single accelerator or requires partitioning across multiple devices.

The MI300A, by contrast, wins on memory bandwidth. Its memory runs at 2525 MHz with 10.1 Gbps effective data rate, producing a bandwidth of 10.3 TB/s. The MI325X runs memory at 1500 MHz with 6 Gbps effective, yielding 6.14 TB/s. That is a 4.16 TB/s advantage for the MI300A, a difference of roughly 68% more bandwidth. For memory-bound kernels, such as sparse matrix operations, graph processing, or certain data movement patterns in scientific computing, the higher bandwidth can translate into shorter execution times despite the smaller capacity.

The MI300A also wins on FP16 compute throughput. It delivers 653.7 TFLOPS of FP16 performance using an 8:1 ratio, whereas the MI325X delivers 81.72 TFLOPS of FP16 with a 1:1 ratio. This is a massive difference: the MI300A offers approximately 8 times the FP16 throughput of the MI325X. That places the MI300A in a different class for mixed-precision workloads that rely on FP16 accumulation, including many deep learning training loops and certain HPC applications that exploit reduced precision.

The MI300A also holds an advantage in power efficiency from a thermal design standpoint. Its TDP is 750 W, while the MI325X is rated at 1000 W. The suggested power supply for the MI300A is 1150 W, versus 1400 W for the MI325X. Since both share the same FP32 compute and the MI300A provides higher memory bandwidth and FP16 throughput, the MI300A delivers more performance per watt in those specific metrics. However, the MI325X provides more memory capacity per watt, given its 256 GB capacity at 1000 W.

Release timing also differs. The MI300A was released on December 5, 2023, while the MI325X followed on October 9, 2024. The MI300A's predecessor is listed as FirePro Data Center, and the MI325X's predecessor is listed as Radeon Instinct. Neither part has a recorded successor in the database.

FAQ

Q: Which accelerator has more memory capacity?

A: The AMD Instinct MI325X has 256 GB of HBM3e memory, while the AMD Radeon Instinct MI300A has 192 GB of HBM3 memory. The MI325X provides 64 GB more capacity.

Q: Which accelerator has higher memory bandwidth?

A: The AMD Radeon Instinct MI300A has a memory bandwidth of 10.3 TB/s, compared to the AMD Instinct MI325X's 6.14 TB/s. The MI300A's bandwidth is higher by 4.16 TB/s.

Q: Do these accelerators have the same FP32 compute performance?

A: Yes. Both the AMD Instinct MI325X and the AMD Radeon Instinct MI300A deliver 81.72 TFLOPS of FP32 performance. They also share the same shading unit count of 19,456 and the same texture rate of 2,553.6 GTexel/s.

Q: What is the difference in FP16 throughput?

A: The AMD Radeon Instinct MI300A achieves 653.7 TFLOPS of FP16 performance with an 8:1 ratio, whereas the AMD Instinct MI325X delivers 81.72 TFLOPS with a 1:1 ratio. The MI300A provides approximately 8 times the FP16 throughput.

Q: What are the thermal design power ratings?

A: The AMD Instinct MI325X has a TDP of 1000 W and a suggested power supply of 1400 W. The AMD Radeon Instinct MI300A has a TDP of 750 W and a suggested power supply of 1150 W.

Q: When were these accelerators released?

A: The AMD Radeon Instinct MI300A was released on December 5, 2023. The AMD Instinct MI325X was released on October 9, 2024.

Specification Differences

| Specification | AMD Instinct MI325X | AMD Radeon Instinct MI300A |

|----------------|---------------------|----------------------------|

| Memory Size | 256 GB | 192 GB |

| Memory Type | HBM3e | HBM3 |

| Memory Clock | 1500 MHz, 6 Gbps effective | 2525 MHz, 10.1 Gbps effective |

| Memory Bandwidth | 6.14 TB/s | 10.3 TB/s |

| FP16 Performance | 81.72 TFLOPS (1:1) | 653.7 TFLOPS (8:1) |

| TDP | 1000 W | 750 W |

| Suggested PSU | 1400 W | 1150 W |

| Release Date | 2024-10-09 | 2023-12-05 |

| Predecessor | Radeon Instinct | FirePro Data Center |

| DirectX API | N/A | null |

| OpenGL API | N/A | null |

| Vulkan API | N/A | null |

All other recorded specifications are identical between the two parts. Both use the same chip, the same 5 nm process node from TSMC, the same transistor count of 153,000 million, the same die size of 1017 mm², the same transistor density of 150.4M per mm², the same base clock of 1000 MHz, the same boost clock of 2100 MHz, the same 8192-bit memory bus width, the same 19,456 shading units, the same 1,216 TMUs, the same 0 ROPs, the same 0 MPixel/s pixel rate, the same 2,553.6 GTexel/s texture rate, the same 81.72 TFLOPS FP32 performance, the same OAM Module slot width, no power connectors, the same PCIe 5.0 x16 bus interface, and no display outputs.

Architecture Differences

Both accelerators are built on the CDNA 3.0 architecture, which is the same architecture generation. They use the same Aqua Vanjaram chip, so the underlying compute architecture is not different between them. The architectural differences that do exist are limited to the memory subsystem and the FP16 execution path.

The MI325X uses HBM3e memory, which is a newer memory standard than the HBM3 used in the MI300A. The HBM3e implementation in the MI325X operates at a lower clock speed of 1500 MHz with 6 Gbps effective, yet the 8192-bit bus width is the same as the MI300A. The MI300A's HBM3 memory runs at a higher clock of 2525 MHz with 10.1 Gbps effective, which explains its higher bandwidth of 10.3 TB/s. The memory capacity difference, 256 GB versus 192 GB, likely arises from different stack configurations, though the database does not specify the number of stacks or dies.

The FP16 throughput difference is notable. The MI325X reports FP16 at 81.72 TFLOPS with a 1:1 ratio, meaning the FP16 rate matches the FP32 rate. The MI300A reports FP16 at 653.7 TFLOPS with an 8:1 ratio, indicating that the MI300A has a dedicated FP16 path that is 8 times wider than its FP32 path. This suggests that the MI300A's compute units are designed to execute FP16 operations at a higher rate, likely through packed arithmetic or dual-issue behavior. The MI325X does not expose that capability in the recorded data.

The API support also differs in the database. The MI325X lists DirectX, OpenGL, and Vulkan as "N/A", while the MI300A lists these fields as null. In practical terms, neither accelerator is intended for graphics workloads; both have no display outputs and a pixel rate of 0 MPixel/s. The null versus "N/A" designation is a data representation difference, not a functional one.

The power architecture differs as well. The MI325X has a TDP of 1000 W, which is 250 W higher than the MI300A's 750 W. The suggested power supply scales accordingly, with the MI325X requiring 1400 W and the MI300A requiring 1150 W. Both use OAM Module slot width and have no power connectors, so the power delivery is handled through the module interface.

Process node and foundry are identical: 5 nm TSMC. Transistor count and die size are identical. The clock speeds for the compute cores are identical. The only clock difference is the memory clock, which is lower on the MI325X but with newer memory technology.

In terms of generation, both belong to the Instinct family, though the MI300A is listed under Radeon Instinct (MIx) and the MI325X under Instinct (MIx). The MI300A's predecessor is FirePro Data Center, while the MI325X's predecessor is Radeon Instinct. The MI300A released earlier, in December 2023, and the MI325X followed in October 2024. Neither has a successor recorded in the database.

The architectural summary is that these are the same silicon with different memory configurations and different FP16 capabilities. The MI325X favors capacity, the MI300A favors bandwidth and mixed-precision throughput. The absence of benchmark scores means the database cannot confirm which accelerator performs better in real workloads, but the specifications indicate that the choice depends on whether the workload is capacity-bound or bandwidth/FP16-bound.