AMD Instinct MI300A vs NVIDIA RTX A400 Comparison

# AMD Instinct MI300A vs NVIDIA RTX A400

The AMD Instinct MI300A and NVIDIA RTX A400 occupy opposite ends of the accelerator spectrum. The MI300A is a 750 W OAM module built on CDNA 3.0 with 153,000 million transistors, while the RTX A400 is a 50 W single-slot workstation card with 8,700 million transistors. The recorded data shows no direct head-to-head benchmark results between the two, but the specification sheets and available workload metrics reveal clear divisions in capability and intended use.

Where Each One Wins

The AMD Instinct MI300A wins in every compute-oriented category where raw throughput and memory capacity define the workload. Its FP32 output is 61.29 TFLOPS, which is 22.6 times the RTX A400's 2.706 TFLOPS. Texture rate follows the same pattern: 1,915.2 GTexel/s versus 42.29 GTexel/s. The MI300A carries 128 GB of HBM3 memory on an 8192-bit bus, delivering 5.32 TB/s of bandwidth. The RTX A400 provides 4 GB of GDDR6 on a 64-bit bus with 96.00 GB/s. For large matrix operations, dense data processing, or memory-bound inference, the MI300A is the only viable option in this pairing.

The NVIDIA RTX A400 wins in areas the MI300A does not address at all. It has 6 RT cores and 24 tensor cores; the MI300A lists no RT or tensor core counts. The A400 supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4, while the MI300A reports N/A for all three APIs. The A400 has 4x mini-DisplayPort 1.4a outputs, and the MI300A has no display outputs. Pixel rate is 28.19 GPixel/s on the A400 versus 0 MPixel/s on the MI300A. The A400's benchmark results, including a Passmark G3D score of 5983 and a Geekbench OpenCL score of 22844, confirm it functions as a working graphics and compute device. The MI300A has no recorded benchmark scores and a 50th percentile ranking against all GPUs, which reflects its absence from consumer benchmark suites rather than a performance deficiency.

Architecture Differences

The MI300A uses the CDNA 3.0 architecture on a 5 nm process from TSMC. The RTX A400 uses the Ampere architecture on an 8 nm process from Samsung. Transistor density diverges sharply: the MI300A packs 150.4 million transistors per square millimeter across a 1017 mm² die, while the RTX A400 achieves 43.5 million per square millimeter on a 200 mm² die. The MI300A's 14592 shading units and 912 TMUs dwarf the A400's 768 shading units and 24 TMUs. The A400 has 16 ROPs; the MI300A has 0 ROPs, consistent with its lack of rasterization hardware.

Memory technology separates the two completely. HBM3 with a 5.2 Gbps effective data rate and 8192-bit interface gives the MI300A 5.32 TB/s bandwidth. GDDR6 at 12 Gbps effective on a 64-bit bus yields 96.00 GB/s for the A400. The MI300A's memory clock is 1300 MHz, and the A400's is 1500 MHz, but bus width overwhelms clock speed in bandwidth calculations. The MI300A also carries a PCIe 5.0 x16 interface, while the A400 uses PCIe 4.0 x8.

Feature support differs by design intent. The A400 includes RT cores, tensor cores, and a full graphics API stack. The MI300A omits these, listing no RT or tensor hardware and no graphics API support. The A400 is a single-slot card measuring 163 mm by 69 mm with four mini-DisplayPort outputs. The MI300A is an OAM module with no power connectors and no display outputs, requiring a 1150 W suggested PSU. The A400's suggested PSU is 250 W.

Head-to-Head Benchmarks

No direct head-to-head benchmark results exist in the database for the MI300A and RTX A400. The MI300A has no benchmark entries, an average score of 0, and no nearest rivals listed. The RTX A400 has nine recorded benchmark scores and an average benchmark score of 6078, placing it in the 35th percentile of all GPUs.

The RTX A400's nearest rivals show its competitive position. The GeForce MX230 scores 6077, a 0% delta. The Quadro P2000 scores 6049, a 0.5% delta. The Intel Iris Pro Graphics 6200 scores 6117, which is 0.6% above the A400. The AMD Radeon 760M scores 6019, 1% below. These results place the A400 in a narrow band around 6000 average score, roughly equivalent to entry-level and older midrange parts.

The A400's individual benchmark scores reveal its workload profile. Passmark G3D is 5983, while Passmark GPU Compute is 2557. The compute-to-graphics ratio is about 0.43, indicating stronger rasterization performance relative to compute throughput. Geekbench OpenCL is 22844 and Geekbench Vulkan is 22237, a close pairing that suggests consistent performance across compute APIs. Passmark DirectX 9 scores 87, DirectX 10 scores 32, DirectX 11 scores 37, and DirectX 12 scores 27. The legacy DirectX 9 result is roughly three times the DirectX 12 result, which is typical for a low-power Ampere part where driver overhead and shader complexity scale with API generation.

The MI300A's FP32 output of 61.29 TFLOPS, when compared to the A400's 2.706 TFLOPS, indicates a 22.6-fold advantage in single-precision compute. Memory bandwidth shows a similar gap: 5.32 TB/s versus 96.00 GB/s, a 55.4-fold difference. The MI300A's texture rate of 1,915.2 GTexel/s is 45.3 times the A400's 42.29 GTexel/s. These ratios define the selection boundary: the MI300A for data-center scale compute, the A400 for workstation graphics and light compute tasks.

FAQ

Q: Which card has higher FP32 compute performance?

A: The AMD Instinct MI300A delivers 61.29 TFLOPS, 22.6 times the NVIDIA RTX A400's 2.706 TFLOPS.

Q: Does the RTX A400 support ray tracing?

A: Yes. The RTX A400 includes 6 RT cores and 24 tensor cores, along with DirectX 12 Ultimate (12_2) support. The MI300A lists no RT cores and no tensor cores.

Q: How much memory bandwidth does each card provide?

A: The MI300A provides 5.32 TB/s from 128 GB of HBM3 on an 8192-bit bus. The RTX A400 provides 96.00 GB/s from 4 GB of GDDR6 on a 64-bit bus.

Q: Can the MI300A output video to a display?

A: No. The MI300A has no display outputs and reports N/A for DirectX, OpenGL, and Vulkan. The RTX A400 has 4x mini-DisplayPort 1.4a outputs and supports all three APIs.

Q: What is the power requirement for each card?

A: The MI300A has a 750 W TDP and a suggested PSU of 1150 W. The RTX A400 has a 50 W TDP and a suggested PSU of 250 W.

Q: How does the RTX A400 compare to its nearest rivals?

A: The A400's average benchmark score is 6078. It sits within 1% of the GeForce MX230 (6077), Quadro P2000 (6049), Intel Iris Pro Graphics 6200 (6117), and AMD Radeon 760M (6019).

Specification Differences

| Field | AMD Instinct MI300A | NVIDIA RTX A400 |

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

| Architecture | CDNA 3.0 | Ampere |

| Process node | 5 nm | 8 nm |

| Foundry | TSMC | Samsung |

| Transistors | 153,000 million | 8,700 million |

| Die size | 1017 mm² | 200 mm² |

| Transistor density | 150.4M / mm² | 43.5M / mm² |

| Base clock | 1000 MHz | 1417 MHz |

| Boost clock | 2100 MHz | 1762 MHz |

| Memory clock | 1300 MHz, 5.2 Gbps effective | 1500 MHz, 12 Gbps effective |

| Memory size | 128 GB | 4 GB |

| Memory type | HBM3 | GDDR6 |

| Memory bus | 8192 bit | 64 bit |

| Memory bandwidth | 5.32 TB/s | 96.00 GB/s |

| Shading units | 14592 | 768 |

| TMUs | 912 | 24 |

| ROPs | 0 | 16 |

| RT cores | Not listed | 6 |

| Tensor cores | Not listed | 24 |

| Pixel rate | 0 MPixel/s | 28.19 GPixel/s |

| Texture rate | 1,915.2 GTexel/s | 42.29 GTexel/s |

| FP32 | 61.29 TFLOPS | 2.706 TFLOPS |

| FP16 | Not listed | 2.706 TFLOPS (1:1) |

| TDP | 750 W | 50 W |

| Slot width | OAM Module | Single-slot |

| Power connectors | None | None |

| Suggested PSU | 1150 W | 250 W |

| Bus interface | PCIe 5.0 x16 | PCIe 4.0 x8 |

| Display outputs | No outputs | 4x mini-DisplayPort 1.4a |

| DirectX | N/A | 12 Ultimate (12_2) |

| OpenGL | N/A | 4.6 |

| Vulkan | N/A | 1.4 |

| Dimensions | Not listed | 163 mm, 69 mm |

| Release date | 2023-12-05 | 2024-04-15 |

| Predecessor | Radeon Instinct | Quadro Turing |

| Successor | Not listed | Workstation Ada |

| Percentile vs all GPUs | 50 | 35 |

| Average benchmark score | 0 | 6078 |

The MI300A is a compute accelerator with no graphics pipeline, built for maximum memory bandwidth and FP32 throughput. The RTX A400 is a low-power workstation card with display output, RT cores, tensor cores, and full graphics API support. The recorded data shows no overlap in workload coverage: one is a server-side compute module, the other a desktop graphics and entry compute device.