AMD Instinct MI455X vs NVIDIA H200 NVL Comparison

Where Each One Wins

The recorded data presents an unusual comparison: the AMD Instinct MI455X has no benchmark entries in the database, while the NVIDIA H200 NVL has a single Geekbench OpenCL score of 334,891. This places the H200 NVL at the 100th percentile among all GPUs, indicating it outperforms virtually every other recorded graphics processor in the database.

The H200 NVL's nearest rival data provides context for its standing. The NVIDIA B200 scores 345,482, which is 3.1% higher than the H200 NVL. The AMD Instinct MI300X trails with 317,994, putting the H200 NVL 5.3% ahead. The NVIDIA B300 SXM6 AC leads the field at 369,831, a 9.4% advantage over the H200 NVL. The NVIDIA L40S sits at 295,763, meaning the H200 NVL is 13.2% faster.

For the MI455X, the absence of benchmark results means the database cannot assign it a competitive position. Its percentile ranking of 50 with an average benchmark score of 0 reflects this data gap rather than actual performance. The wins category shows zero for the AMD part and one for the NVIDIA part, strictly based on recorded benchmark presence.

The practical takeaway from the available data: the H200 NVL delivers measurable compute performance that places it among the top accelerators in the database, while the MI455X's capabilities remain unquantified. Users seeking a validated benchmark score would find the H200 NVL supported by concrete numbers, whereas the MI455X requires relying on its architectural specifications alone.

Architecture Differences

The two accelerators diverge significantly at the architectural level. The AMD Instinct MI455X uses the MI450 256CU chip based on CDNA 5.0 architecture, fabricated on a 2 nm process at TSMC. The NVIDIA H200 NVL employs the GH100 chip built on Hopper architecture, also produced by TSMC but on a 5 nm process.

Transistor counts reveal a substantial gap. The MI455X integrates 320,000 million transistors across a 2990 mm² die, achieving a transistor density of 107.0 million per mm². The H200 NVL contains 80,000 million transistors on an 814 mm² die, with a density of 98.3 million per mm². The AMD part's larger die and higher transistor budget enable a much wider compute configuration.

Shading unit counts underscore this difference. The MI455X carries 32,768 shading units, 1,024 texture mapping units, and no ROPs, resulting in a texture rate of 2,457.6 GTexel/s and a pixel rate of 0 MPixel/s. The H200 NVL has 16,896 shading units, 528 TMUs, 24 ROPs, and 528 tensor cores, producing 942.5 GTexel/s and 42.84 GPixel/s. The AMD design clearly prioritizes raw shader throughput, while the NVIDIA part includes tensor cores for specialized workloads.

Clock behavior differs notably. The MI455X runs at a 1000 MHz base clock with a 2400 MHz boost, while the H200 NVL operates at 1365 MHz base and 1785 MHz boost. Despite the AMD part's lower base clock, its higher boost ceiling and vastly larger shader array deliver far higher peak floating-point rates: 157.3 TFLOPS FP32 and 157.3 TFLOPS FP16 (1:1 ratio) for the MI455X, versus 60.32 TFLOPS FP32 and 120.6 TFLOPS FP16 (2:1 ratio) for the H200 NVL.

Memory architecture presents another major split. The MI455X uses 432 GB of HBM4 on a 24,576-bit bus, yielding 23.3 TB/s of bandwidth at 1900 MHz (7.6 Gbps effective). The H200 NVL uses 141 GB of HBM3e on a 6,144-bit bus, delivering 4.89 TB/s at 1593 MHz (6.4 Gbps effective). The AMD accelerator offers over three times the memory capacity and nearly five times the bandwidth.

Physical and power characteristics differ sharply. The MI455X is an EAM Module with no power connectors and a 2300 W TDP, requiring a 2700 W suggested PSU. It uses PCIe 6.0 x16. The H200 NVL is a dual-slot card with an 8-pin EPS connector, 600 W TDP, and 1000 W suggested PSU, using PCIe 5.0 x16. The H200 NVL measures 267 mm by 111 mm. Neither card has display outputs, and both list DirectX, OpenGL, and Vulkan as N/A.

The MI455X has no production status recorded and a release date of 2026-07-22. Its predecessor is listed as Radeon Instinct. The H200 NVL is marked as Active production, released 2024-11-17, with Server Ada as predecessor and Server Blackwell as successor.

FAQ

Q: Which accelerator has a higher FP32 throughput?

A: The AMD Instinct MI455X delivers 157.3 TFLOPS FP32, compared to 60.32 TFLOPS for the NVIDIA H200 NVL, making the AMD part 2.6 times faster in single-precision floating-point operations.

Q: How does the memory capacity compare between the two?

A: The MI455X offers 432 GB of HBM4 memory, while the H200 NVL provides 141 GB of HBM3e. The AMD accelerator also leads in bandwidth with 23.3 TB/s versus 4.89 TB/s.

Q: What benchmark results exist for each GPU?

A: The database contains no benchmark entries for the MI455X. The H200 NVL has one Geekbench OpenCL score of 334,891, placing it at the 100th percentile among all GPUs.

Q: How does the H200 NVL compare to its nearest rivals?

A: The H200 NVL is 3.1% behind the NVIDIA B200, 5.3% ahead of the AMD Instinct MI300X, 9.4% behind the NVIDIA B300 SXM6 AC, and 13.2% ahead of the NVIDIA L40S.

Q: What are the power requirements for each card?

A: The MI455X has a 2300 W TDP with a suggested PSU of 2700 W and no power connectors. The H200 NVL has a 600 W TDP with a suggested PSU of 1000 W and uses an 8-pin EPS connector.

Q: Which architecture and process node does each use?

A: The MI455X uses CDNA 5.0 architecture on a 2 nm TSMC process. The H200 NVL uses Hopper architecture on a 5 nm TSMC process.

Specification Differences

| Specification | AMD Instinct MI455X | NVIDIA H200 NVL |

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

| Chip | MI450 256CU | GH100 |

| Architecture | CDNA 5.0 | Hopper |

| Generation | Instinct (MIx) | Server Hopper (Hxx) |

| Process Node | 2 nm | 5 nm |

| Transistors | 320,000 million | 80,000 million |

| Die Size | 2990 mm² | 814 mm² |

| Transistor Density | 107.0M / mm² | 98.3M / mm² |

| Base Clock | 1000 MHz | 1365 MHz |

| Boost Clock | 2400 MHz | 1785 MHz |

| Memory Clock | 1900 MHz 7.6 Gbps effective | 1593 MHz 6.4 Gbps effective |

| Memory Size | 432 GB | 141 GB |

| Memory Type | HBM4 | HBM3e |

| Memory Bus Width | 24576 bit | 6144 bit |

| Memory Bandwidth | 23.3 TB/s | 4.89 TB/s |

| Shading Units | 32768 | 16896 |

| TMUs | 1024 | 528 |

| ROPs | 0 | 24 |

| Tensor Cores | Not specified | 528 |

| Pixel Rate | 0 MPixel/s | 42.84 GPixel/s |

| Texture Rate | 2,457.6 GTexel/s | 942.5 GTexel/s |

| FP32 | 157.3 TFLOPS | 60.32 TFLOPS |

| FP16 | 157.3 TFLOPS (1:1) | 120.6 TFLOPS (2:1) |

| TDP | 2300 W | 600 W |

| Slot Width | EAM Module | Dual-slot |

| Power Connectors | None | 8-pin EPS |

| Suggested PSU | 2700 W | 1000 W |

| Bus Interface | PCIe 6.0 x16 | PCIe 5.0 x16 |

| Length | Not specified | 267 mm 10.5 inches |

| Height | Not specified | 111 mm 4.4 inches |

| Production Status | Not specified | Active |

| Release Date | 2026-07-22 | 2024-11-17 |

| Predecessor | Radeon Instinct | Server Ada |

| Successor | Not specified | Server Blackwell |

Head-to-Head Benchmarks

The database records no head-to-head benchmark entries between the MI455X and the H200 NVL. The only measurable performance point belongs to the NVIDIA part: a Geekbench OpenCL score of 334,891. This single data point cannot establish a direct comparison, but it does anchor the H200 NVL's position in the broader GPU landscape.

Against its nearest rivals, the H200 NVL's score translates into specific percentage deltas. The NVIDIA B200 leads by 3.1%, a modest margin that suggests the two accelerators operate in a similar performance tier. The B300 SXM6 AC extends that lead to 9.4%, representing a more substantial gap. On the trailing side, the AMD Instinct MI300X sits 5.3% behind, and the NVIDIA L40S falls 13.2% short. These deltas position the H200 NVL as a strong mid-to-upper performer among current accelerators.

The MI455X's architectural specifications, however, point to capabilities that could theoretically exceed the H200 NVL's measured results. With 157.3 TFLOPS FP32 versus 60.32 TFLOPS, the AMD part claims 2.6 times the single-precision throughput. Its FP16 output of 157.3 TFLOPS (1:1) also surpasses the H200 NVL's 120.6 TFLOPS (2:1). Memory bandwidth favors the MI455X by a wide margin: 23.3 TB/s versus 4.89 TB/s, a 4.8 times difference. Memory capacity follows the same pattern, with 432 GB versus 141 GB.

The absence of MI455X benchmark data means these specification advantages remain theoretical. The database cannot confirm whether the AMD accelerator's higher peak rates translate into real-world performance gains. The H200 NVL, by contrast, has a validated score at the 100th percentile, meaning it outperforms all other GPUs in the database with recorded measurements.

Texture throughput also favors the AMD part: 2,457.6 GTexel/s versus 942.5 GTexel/s. The H200 NVL counters with a nonzero pixel rate of 42.84 GPixel/s, while the MI455X lists 0 MPixel/s, reflecting its lack of ROPs. The NVIDIA card's tensor cores, 528 of them, provide dedicated hardware for matrix operations that the MI455X does not specify.

Clock speeds tell a mixed story. The H200 NVL runs higher at idle with a 1365 MHz base clock, while the MI455X starts at 1000 MHz. Boost clocks reverse the order: the MI455X reaches 2400 MHz, far above the H200 NVL's 1785 MHz. The AMD part's higher boost, combined with its massive shader array, explains its elevated TFLOPS figures.

Power consumption scales with these specifications. The MI455X demands 2300 W TDP and a 2700 W suggested PSU, while the H200 NVL operates at 600 W TDP with a 1000 W suggested PSU. The AMD accelerator's power envelope is nearly four times larger, consistent with its wider memory bus and higher clock ceiling.

The production status field shows the H200 NVL as Active, while the MI455X has no recorded status. Release dates place the H200 NVL in November 2024 and the MI455X in July 2026, suggesting the AMD part is a newer design. The MI455X's successor field is empty, while the H200 NVL lists Server Blackwell as its successor, indicating NVIDIA has already moved past this generation.

For anyone relying on benchmark data, the H200 NVL stands as the only option with a recorded score. Its 334,891 Geekbench OpenCL result, coupled with its 100th percentile ranking, provides a concrete performance reference. The MI455X, despite its impressive specifications, currently offers no measured evidence in the database to support its claimed capabilities.