AMD Instinct MI308X vs NVIDIA RTX A400 Comparison

FAQ

Q: What are the core architectural identities of these two accelerators?

A: The AMD Instinct MI308X is a CDNA 3.0 compute accelerator built on TSMC's 5 nm process, using the Aqua Vanjaram chip with 153,000 million transistors on a 1017 mm² die. The NVIDIA RTX A400 is an Ampere workstation GPU built on Samsung's 8 nm process, using the GA107 chip with 8,700 million transistors on a 200 mm² die.

Q: How do the memory subsystems compare?

A: The MI308X uses 192 GB of HBM3 on an 8192-bit bus, delivering 5.32 TB/s of bandwidth. The RTX A400 uses 4 GB of GDDR6 on a 64-bit bus, delivering 96.00 GB/s of bandwidth. The MI308X has 54 times the memory capacity and over 55 times the bandwidth of the A400.

Q: What is the performance percentile ranking for each card?

A: The MI308X sits at the 50th percentile among all GPUs in the database, while the RTX A400 sits at the 35th percentile. The MI308X has an average benchmark score of 0, while the RTX A400 has an average benchmark score of 6078.

Q: What are the closest rivals to the RTX A400?

A: The nearest rivals to the RTX A400 are the NVIDIA GeForce MX230 (average score 6077, 0% delta), NVIDIA Quadro P2000 (average score 6049, 0.5% delta), Intel Iris Pro Graphics 6200 (average score 6117, -0.6% delta), and AMD Radeon 760M (average score 6019, 1% delta). The A400 effectively trades blows with these parts.

Q: What display outputs does each card provide?

A: The RTX A400 provides 4x mini-DisplayPort 1.4a outputs. The MI308X provides no display outputs at all, as it is an OAM module compute part.

Q: What is the release timeline for both products?

A: The MI308X was released on 2023-12-05, while the RTX A400 was released on 2024-04-15. The MI308X belongs to the Instinct (MIx) generation, succeeding Radeon Instinct, while the RTX A400 belongs to the Workstation Ampere (Ax000) generation, succeeding Quadro Turing and succeeded by Workstation Ada.

Architecture Differences

The two accelerators diverge at nearly every architectural level. The MI308X uses AMD's CDNA 3.0 architecture, a compute-focused design with no graphics pipeline support. Its API support is marked as N/A for DirectX, OpenGL, and Vulkan, confirming that it is not intended for rasterization or ray tracing workloads. The RTX A400 uses NVIDIA's Ampere architecture, which includes full graphics capabilities: DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4 support.

The compute resources differ by an order of magnitude. The MI308X contains 19,456 shading units, 1,216 texture mapping units, and 0 ROPs. The RTX A400 contains 768 shading units, 24 TMUs, and 16 ROPs. The MI308X has no RT cores or tensor cores listed, while the RTX A400 includes 6 RT cores and 24 tensor cores.

Manufacturing processes also separate the two. The MI308X is fabricated on TSMC's 5 nm node with a transistor density of 150.4M per mm². The RTX A400 is fabricated on Samsung's 8 nm node with a transistor density of 43.5M per mm². The MI308X packs 17.6 times more transistors onto a die that is 5.1 times larger.

Clock behavior differs as well. The MI308X has a base clock of 1000 MHz and a boost clock of 2100 MHz. The RTX A400 has a base clock of 1417 MHz and a boost clock of 1762 MHz. Despite the RTX A400's higher base clock, the MI308X achieves a higher boost clock and massively higher throughput from its wider execution resources.

The MI308X is an OAM module with no power connectors and no display outputs. The RTX A400 is a single-slot card measuring 163 mm by 69 mm, drawing power from the PCIe slot, and offering 4x mini-DisplayPort 1.4a outputs. The MI308X uses a PCIe 5.0 x16 interface, while the RTX A400 uses a PCIe 4.0 x8 interface.

Where Each One Wins

The MI308X is designed for compute density. Its 192 GB HBM3 memory pool and 5.32 TB/s bandwidth make it suitable for large-scale data residency, where entire datasets or model weights need to fit in on-chip memory. The 81.72 TFLOPS FP32 throughput and 81.72 TFLOPS FP16 throughput (1:1 ratio) provide massive parallelism for floating-point workloads. The 2,553.6 GTexel/s texture rate further indicates raw processing capability, though the 0 MPixel/s pixel rate shows it cannot rasterize frames.

The RTX A400 is designed for workstation graphics and lightweight compute. Its 28.19 GPixel/s pixel rate and 42.29 GTexel/s texture rate, combined with 6 RT cores and 24 tensor cores, make it suited for rendering, ray-traced workflows, and AI-accelerated tasks in a desktop form factor. The 4x mini-DisplayPort 1.4a outputs allow multi-monitor configurations. The 50 W TDP and single-slot design allow deployment in compact workstations where power and space are constrained.

The benchmark data for the RTX A400 shows its strengths in specific API tests. It scores 22,844 in Geekbench OpenCL and 22,237 in Geekbench Vulkan, indicating solid general-purpose compute performance for its class. In Passmark tests, it scores 87 in DirectX 9, 37 in DirectX 11, 32 in DirectX 10, and 27 in DirectX 12. Its Passmark G2D score of 899 and G3D score of 5983 confirm usable 2D and 3D acceleration. The Passmark GPU compute score of 2557 shows modest compute throughput.

The MI308X has no benchmark entries in the database, so its measured performance cannot be compared directly. Its architectural specifications, however, place it in a completely different performance class. The data shows that these products target different segments: the MI308X for server-side acceleration with no display path, and the RTX A400 for workstation graphics with full display and API support.

Specification Differences

| Specification | AMD Instinct MI308X | 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 size | 192 GB | 4 GB |

| Memory type | HBM3 | GDDR6 |

| Memory bus width | 8192 bit | 64 bit |

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

| Shading units | 19,456 | 768 |

| TMUs | 1,216 | 24 |

| ROPs | 0 | 16 |

| RT cores | None listed | 6 |

| Tensor cores | None listed | 24 |

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

| Texture rate | 2,553.6 GTexel/s | 42.29 GTexel/s |

| FP32 | 81.72 TFLOPS | 2.706 TFLOPS |

| FP16 | 81.72 TFLOPS (1:1) | 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 support | N/A | 12 Ultimate (12_2) |

| OpenGL support | N/A | 4.6 |

| Vulkan support | N/A | 1.4 |

| Dimensions | Not listed | 163 mm 6.4 inches length, 69 mm 2.7 inches height |

| Production status | Not listed | Active |

Head-to-Head Benchmarks

The database contains no direct head-to-head benchmark entries between the MI308X and RTX A400. The MI308X has no recorded benchmark scores, while the RTX A400 has a full set of measurements. The comparison therefore relies on the recorded data for the RTX A400 and the architectural specifications for both.

The RTX A400's strongest recorded result is its Geekbench OpenCL score of 22,844. Its Geekbench Vulkan score of 22,237 is nearly as high, showing balanced performance across the two compute APIs. These scores place the A400 near the performance of its nearest rivals: the GeForce MX230 (6077, 0% delta), Quadro P2000 (6049, 0.5% delta), Iris Pro Graphics 6200 (6117, -0.6% delta), and Radeon 760M (6019, 1% delta).

The Passmark suite reveals the A400's varying strength across DirectX versions. The DirectX 9 score of 87 is the highest among the Passmark graphics tests, while DirectX 11 scores 37, DirectX 10 scores 32, and DirectX 12 scores 27. This pattern indicates stronger legacy API performance relative to modern API workloads. The Passmark G3D score of 5983 and G2D score of 899 show the card's overall graphics capability, while the GPU compute score of 2557 reflects its compute throughput.

The MI308X's FP32 rating of 81.72 TFLOPS is 30.2 times higher than the RTX A400's 2.706 TFLOPS. Its FP16 rating matches its FP32 rating at a 1:1 ratio, also 81.72 TFLOPS, while the A400's FP16 is 2.706 TFLOPS at the same 1:1 ratio. The MI308X texture rate of 2,553.6 GTexel/s is 60.4 times higher than the A400's 42.29 GTexel/s. The MI308X memory bandwidth of 5.32 TB/s exceeds the A400's 96.00 GB/s by a factor of 55.4.

The MI308X carries a 750 W TDP and suggests an 1150 W power supply. The RTX A400 carries a 50 W TDP and suggests a 250 W power supply. The MI308X uses PCIe 5.0 x16, while the A400 uses PCIe 4.0 x8. The A400 measures 163 mm in length and 69 mm in height, while the MI308X dimensions are not listed in the database.

The recorded data confirms that these are not competing products in the conventional sense. The MI308X targets compute acceleration with no graphics path, while the RTX A400 targets workstation graphics with full API support. Their benchmark results, where available, reflect these distinct roles. The A400's percentile rank of 35 places it below the MI308X's percentile rank of 50, though the MI308X's average benchmark score of 0 means no measured workload confirms that ranking. The architectural specifications, however, show a decisive performance gap in raw compute metrics across FP32, FP16, texture rate, and memory bandwidth.