AMD Instinct MI300A vs AMD Instinct MI325X Comparison

FAQ

Q: What are the core architectural similarities between the MI300A and MI325X?

A: Both accelerators are built on the same foundation. They share the Aqua Vanjaram chip, the CDNA 3.0 architecture, a 5 nm process node at TSMC, and an identical transistor count of 153,000 million. Both also use the same 1017 mm² die size.

Q: How does the memory configuration differ between the two?

A: The MI300A uses 128 GB of HBM3 memory with a 5.32 TB/s bandwidth, while the MI325X uses 256 GB of HBM3e memory with a 6.14 TB/s bandwidth. Both have an 8192-bit memory bus.

Q: What are the clock speed differences?

A: The base clock is identical at 1000 MHz for both, and the boost clock is also the same at 2100 MHz. However, the memory clock differs, with the MI300A running at 1300 MHz (5.2 Gbps effective) and the MI325X running at 1500 MHz (6 Gbps effective).

Q: How do the compute resources compare?

A: The MI325X has significantly more compute units. It features 19,456 shading units and 1,216 TMUs, compared to 14,592 shading units and 912 TMUs on the MI300A. This translates to a higher texture rate of 2,553.6 GTexel/s for the MI325X versus 1,915.2 GTexel/s for the MI300A.

Q: What are the power consumption differences?

A: The MI325X has a higher thermal design power (TDP) of 1000 W, while the MI300A is rated at 750 W. The suggested power supply also differs, with the MI325X requiring a 1400 W PSU and the MI300A a 1150 W PSU.

Q: When were these accelerators released?

A: The MI300A was released on December 5, 2023, while the MI325X was released on October 9, 2024, making the MI325X the newer product by roughly ten months.

Architecture Differences

Both the AMD Instinct MI300A and the AMD Instinct MI325X are built on the same fundamental architecture, which makes their differences particularly instructive. The two accelerators share the Aqua Vanjaram chip, the CDNA 3.0 architecture, a 5 nm manufacturing process at TSMC, and an identical transistor count of 153,000 million. The die size is also exactly the same at 1017 mm², with the same transistor density of 150.4 million transistors per square millimeter.

The most significant architectural divergence lies in the memory subsystem. The MI300A uses HBM3 memory with 128 GB of capacity, while the MI325X uses HBM3e memory with double the capacity at 256 GB. The memory bus width is identical at 8192 bits for both, but the MI325X's HBM3e technology operates at a higher memory clock of 1500 MHz (6 Gbps effective) compared to the MI300A's 1300 MHz (5.2 Gbps effective). This results in a bandwidth advantage for the MI325X, which delivers 6.14 TB/s versus the MI300A's 5.32 TB/s.

The compute architecture also differs substantially. The MI325X packs 19,456 shading units and 1,216 texture mapping units (TMUs), while the MI300A has 14,592 shading units and 912 TMUs. Both accelerators have zero ROPs and produce 0 MPixel/s pixel rates, reflecting their compute-optimized design rather than a graphics-oriented one. The texture rate scales with the unit counts, giving the MI325X a 2,553.6 GTexel/s rate versus 1,915.2 GTexel/s for the MI300A.

The floating-point performance reflects these differences. The MI325X achieves 81.72 TFLOPS for FP32 operations, while the MI300A achieves 61.29 TFLOPS. Notably, the MI325X also lists FP16 performance at 81.72 TFLOPS with a 1:1 ratio, while the MI300A's FP16 figure is not recorded in the database.

Power delivery requirements scale accordingly. The MI325X carries a TDP of 1000 W with a suggested power supply of 1400 W, while the MI300A has a TDP of 750 W and a suggested PSU of 1150 W. Both use OAM Module slot widths with no power connectors listed and no display outputs, confirming their purpose as data center accelerators rather than consumer graphics cards. Both use a PCIe 5.0 x16 bus interface.

Head-to-Head Benchmarks

The recorded benchmark data between the AMD Instinct MI300A and the AMD Instinct MI325X shows no individual test results in the database, which means the comparison must be drawn from the architectural specifications and the derived performance metrics available in the database.

The most prominent lead for the MI325X comes in FP32 compute throughput. The MI325X delivers 81.72 TFLOPS, which is 33.3% higher than the MI300A's 61.29 TFLOPS. This is a substantial margin for any compute workload that relies on single-precision arithmetic, and it directly follows from the higher shading unit count of 19,456 versus 14,592.

Memory bandwidth is another clear win for the MI325X. The 6.14 TB/s figure represents a 15.4% improvement over the MI300A's 5.32 TB/s. Combined with double the memory capacity, the MI325X can feed its larger compute array more effectively, particularly for workloads with large working sets that exceed the MI300A's 128 GB capacity.

The texture rate also favors the MI325X. At 2,553.6 GTexel/s, the MI325X outperforms the MI300A's 1,915.2 GTexel/s by 33.3%, mirroring the FP32 advantage exactly since both scale from the same TMU counts.

The MI325X also adds FP16 capability at 81.72 TFLOPS, a figure that matches its FP32 output. The MI300A does not have a recorded FP16 figure in the database, which means for mixed-precision workloads the MI325X has a documented capability that the MI300A cannot match based on available data.

The MI300A does hold advantages in power efficiency. Its TDP of 750 W is 25% lower than the MI325X's 1000 W. When considering FP32 throughput per watt, the MI300A delivers approximately 81.72 TFLOPS per 1000 W equivalent, the MI300A achieves 61.29 TFLOPS at 750 W, which computes to 81.72 TFLOPS per 1000 W for the MI325X and 81.72 TFLOPS per 1000 W for the MI300A. In fact, the MI300A delivers 81.72 TFLOPS per 1000 W, while the MI325X delivers 81.72 TFLOPS per 1000 W, indicating identical efficiency per watt despite the MI325X's higher absolute performance. The raw efficiency calculation shows the MI300A achieves 81.72 TFLOPS per 1000 W, and the MI325X achieves 81.72 TFLOPS per 1000 W, meaning the MI300A matches the MI325X in performance-per-watt for FP32 workloads.

The MI300A also has a lower system power requirement, with a suggested PSU of 1150 W versus 1400 W for the MI325X. This makes the MI300A easier to integrate into existing power infrastructure.

Neither accelerator shows any advantage in pixel rate, as both produce 0 MPixel/s, nor do they differ in API support, with both listing N/A for DirectX, OpenGL, and Vulkan.

Specification Differences

The database records several fields where the two accelerators differ:

| Specification | MI300A | MI325X |

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

| Memory Size | 128 GB | 256 GB |

| Memory Type | HBM3 | HBM3e |

| Memory Clock | 1300 MHz, 5.2 Gbps effective | 1500 MHz, 6 Gbps effective |

| Memory Bandwidth | 5.32 TB/s | 6.14 TB/s |

| Shading Units | 14,592 | 19,456 |

| TMUs | 912 | 1,216 |

| Texture Rate | 1,915.2 GTexel/s | 2,553.6 GTexel/s |

| FP32 Performance | 61.29 TFLOPS | 81.72 TFLOPS |

| FP16 Performance | Not recorded | 81.72 TFLOPS (1:1) |

| TDP | 750 W | 1000 W |

| Suggested PSU | 1150 W | 1400 W |

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

Fields that are identical between the two include the chip (Aqua Vanjaram), architecture (CDNA 3.0), generation (Instinct MIx), process node (5 nm), foundry (TSMC), transistors (153,000 million), die size (1017 mm²), transistor density (150.4M per mm²), base clock (1000 MHz), boost clock (2100 MHz), memory bus width (8192 bit), pixel rate (0 MPixel/s), TDP class (OAM Module), power connectors (None), bus interface (PCIe 5.0 x16), display outputs (No outputs), APIs (all N/A), and predecessor (Radeon Instinct). Neither accelerator lists a launch MSRP in the database.

The Verdict

The data indicates that the AMD Instinct MI325X is the more capable accelerator in almost every compute metric. It delivers 81.72 TFLOPS of FP32 performance, which is 33.3% higher than the MI300A's 61.29 TFLOPS. It doubles the memory capacity to 256 GB, increases bandwidth by 15.4% to 6.14 TB/s, and adds recorded FP16 capability at 81.72 TFLOPS. For workloads that can utilize the larger memory pool and higher compute throughput, the MI325X is the clear choice.

The MI300A retains advantages in power consumption. At 750 W TDP with a suggested 1150 W PSU, it requires substantially less power infrastructure than the MI325X's 1000 W TDP and 1400 W suggested PSU. For deployments where power delivery is constrained or where the workload does not require the MI325X's additional capacity, the MI300A remains a viable option. Its performance-per-watt for FP32 is equal to the MI325X, meaning the efficiency is identical, but the absolute performance is lower.

The release timeline also matters. The MI300A launched on December 5, 2023, while the MI325X followed on October 9, 2024. The later release date of the MI325X aligns with its more advanced HBM3e memory technology and larger compute configuration.

For organizations prioritizing maximum FP32 throughput and memory capacity, the MI325X is the stronger choice. For those with power constraints or workloads that fit within 128 GB of memory, the MI300A offers the same efficiency with a lower power draw. The database records no individual benchmark scores for either accelerator, so the comparison rests entirely on the documented specification differences. Both accelerators share the same percentile ranking of 50 among all GPUs in the database, reflecting their similar standing in the overall performance distribution.