AMD Instinct MI308X vs NVIDIA H20 Comparison

The Verdict

The AMD Instinct MI308X and NVIDIA H20 target different segments of the accelerator market, and the recorded data shows a clear split. The MI308X is the capacity and raw compute play, with 192 GB of HBM3 memory, 8192 bit bus width, and 81.72 TFLOPS FP32 throughput. The H20 is the efficiency-focused server part, with 96 GB memory, 6144 bit bus, and 39.54 TFLOPS FP32. Neither part has any benchmark scores recorded, so the verdict rests entirely on specification analysis rather than measured performance.

For workloads that demand maximum memory capacity and memory bandwidth, the MI308X is the clear choice. Its 192 GB frame buffer is double the H20's 96 GB, and its 5.32 TB/s bandwidth exceeds the H20's 4.03 TB/s by a substantial margin. For multi-GPU deployments where power density and thermal budgets are primary constraints, the H20's 500 W TDP versus the MI308X's 750 W TDP makes it the more manageable option. The H20 also carries active production status, while the MI308X's production status is not recorded, which may matter for procurement decisions.

The MI308X uses CDNA 3.0 architecture on TSMC 5 nm with 153,000 million transistors on a 1017 mm² die. The H20 uses Hopper architecture, also on TSMC 5 nm, with 80,000 million transistors on an 814 mm² die. The transistor density difference is notable: 150.4M per mm² for the MI308X versus 98.3M per mm² for the H20. This indicates AMD packed significantly more logic into each square millimeter, which aligns with the MI308X's higher shading unit count of 19,456 versus 9,984 for the H20.

Where Each One Wins

The MI308X wins decisively in memory capacity and raw compute throughput. Its 192 GB memory configuration supports larger model footprints without sharding across multiple GPUs. The 8192 bit memory bus is the widest recorded in this comparison, enabling 5.32 TB/s of bandwidth. In FP32 compute, the MI308X delivers 81.72 TFLOPS, which is more than double the H20's 39.54 TFLOPS. Texture rate follows the same pattern: 2,553.6 GTexel/s versus 617.8 GTexel/s. The MI308X has 1,216 TMUs compared to the H20's 312.

The H20 wins in power efficiency and operational flexibility. Its 500 W TDP is one-third lower than the MI308X's 750 W. The suggested power supply requirement is 900 W versus 1,150 W for the MI308X, indicating a lower system-level power infrastructure burden. The H20's base clock of 1,830 MHz is significantly higher than the MI308X's 1,000 MHz base, and its boost clock of 1,980 MHz approaches the MI308X's 2,100 MHz boost. This suggests the H20 maintains higher clocks at lower power, though the MI308X compensates with far more execution units.

The H20 also has a smaller die footprint at 814 mm² versus 1,017 mm², which could translate to better manufacturing yield characteristics, though the database does not record yield data. The H20 includes 312 tensor cores, while the MI308X's tensor core count is not recorded. The H20's FP16 throughput of 79.07 TFLOPS with 2:1 ratio is close to its FP32 rate, while the MI308X records FP16 at 81.72 TFLOPS with 1:1 ratio, meaning the MI308X does not gain a throughput advantage from reduced precision.

Architecture Differences

The MI308X uses CDNA 3.0 architecture on the Aqua Vanjaram chip. The H20 uses Hopper architecture on the GH100 chip. Both are fabricated on TSMC 5 nm, but the transistor counts diverge sharply: 153,000 million for the MI308X versus 80,000 million for the H20. The MI308X's die size of 1,017 mm² is 203 mm² larger than the H20's 814 mm². The transistor density of 150.4M per mm² for the MI308X versus 98.3M per mm² for the H20 indicates AMD achieved a much denser design.

Memory architecture differs fundamentally. The MI308X uses an 8192 bit bus with HBM3 memory at 1,300 MHz (5.2 Gbps effective), yielding 5.32 TB/s. The H20 uses a 6144 bit bus with HBM3 at 1,313 MHz (5.3 Gbps effective), yielding 4.03 TB/s. The MI308X's memory clock is slightly lower, but the wider bus more than compensates, producing 1.29 TB/s additional bandwidth. The MI308X has no ROPs recorded (0 MPixel/s pixel rate), while the H20 has 24 ROPs and a 47.52 GPixel/s pixel rate. This suggests the MI308X is not designed for traditional rasterization workloads, while the H20 retains some pixel processing capability.

The MI308X has 19,456 shading units and 1,216 TMUs. The H20 has 9,984 shading units and 312 TMUs. The MI308X's texture rate of 2,553.6 GTexel/s is 4.1 times the H20's 617.8 GTexel/s. Both parts have no display outputs and no graphics API support (DirectX, OpenGL, Vulkan all N/A). Both use PCIe 5.0 x16 bus interface. The MI308X is an OAM module with no power connectors; the H20 is an SXM module with no power connector data recorded.

Clock behavior shows different strategies. The MI308X has a 1,000 MHz base and 2,100 MHz boost with a 1,100 MHz spread. The H20 has a 1,830 MHz base and 1,980 MHz boost with only a 150 MHz spread. The H20 operates much closer to its maximum clock continuously, while the MI308X likely relies on thermal headroom to reach boost states, though the database does not record actual sustained clock behavior.

FAQ

Q: Which GPU has more memory bandwidth?

A: The MI308X records 5.32 TB/s, while the H20 records 4.03 TB/s. The MI308X leads by 1.29 TB/s due to its 8192 bit bus compared to the H20's 6144 bit bus.

Q: How do the transistor counts compare?

A: The MI308X has 153,000 million transistors, while the H20 has 80,000 million. The MI308X also has a higher transistor density at 150.4M per mm² versus 98.3M per mm² for the H20.

Q: Which GPU requires less power infrastructure?

A: The H20 has a 500 W TDP and a suggested PSU of 900 W. The MI308X has a 750 W TDP and a suggested PSU of 1,150 W.

Q: Can either GPU output video signals?

A: No. Both record "No outputs" for display outputs, and both have N/A for DirectX, OpenGL, and Vulkan APIs.

Q: What memory type and capacity does each use?

A: Both use HBM3. The MI308X has 192 GB, and the H20 has 96 GB.

Q: Which GPU has more shading units?

A: The MI308X has 19,456 shading units, which is 9,472 more than the H20's 9,984.

Head-to-Head Benchmarks

The database records no benchmark scores for either GPU. The winsA and winsB fields are both 0, and the headToHeadBenchmarks array is empty. The percentileVsAllGpus field is 50 for both, indicating both sit at the median of all recorded GPUs, though this percentile is based on an average benchmark score of 0 for each. This absence of measured data means the comparison must rely on specification deltas.

The largest specification win for the MI308X is memory capacity at 192 GB versus 96 GB, a doubling. The second largest is FP32 compute at 81.72 TFLOPS versus 39.54 TFLOPS, a 42.18 TFLOPS difference. The shading unit count difference of 9,472 units is also substantial. The TMU difference of 904 units (1,216 versus 312) drives the texture rate gap of 1,935.8 GTexel/s.

The H20's biggest specification win is its lower TDP at 500 W versus 750 W, a 250 W difference. The H20 also has a higher base clock at 1,830 MHz versus 1,000 MHz, an 830 MHz advantage. The H20's pixel rate of 47.52 GPixel/s versus 0 MPixel/s for the MI308X represents a functional capability that the MI308X lacks entirely.

In FP16 compute, the MI308X records 81.72 TFLOPS with a 1:1 ratio, meaning there is no throughput boost from using reduced precision. The H20 records 79.07 TFLOPS with a 2:1 ratio, meaning it achieves nearly double its FP32 rate in FP16. This gives the H20 a 79.07 TFLOPS FP16 capability that nearly matches the MI308X's 81.72 TFLOPS, despite the MI308X's much larger FP32 lead. For workloads that can exploit FP16, the H20 becomes competitive despite its smaller overall compute budget.

The memory clock difference is minor: 1,300 MHz for the MI308X versus 1,313 MHz for the H20. The effective data rates are 5.2 Gbps and 5.3 Gbps respectively. The bandwidth gap comes almost entirely from the bus width difference.

Specification Differences

| Specification | AMD Instinct MI308X | NVIDIA H20 |

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

| Architecture | CDNA 3.0 | Hopper |

| Process Node | 5 nm (TSMC) | 5 nm (TSMC) |

| Transistors | 153,000 million | 80,000 million |

| Die Size | 1017 mm² | 814 mm² |

| Transistor Density | 150.4M / mm² | 98.3M / mm² |

| Base Clock | 1000 MHz | 1830 MHz |

| Boost Clock | 2100 MHz | 1980 MHz |

| Memory Clock | 1300 MHz (5.2 Gbps effective) | 1313 MHz (5.3 Gbps effective) |

| Memory Size | 192 GB | 96 GB |

| Memory Type | HBM3 | HBM3 |

| Memory Bus Width | 8192 bit | 6144 bit |

| Memory Bandwidth | 5.32 TB/s | 4.03 TB/s |

| Shading Units | 19456 | 9984 |

| TMUs | 1216 | 312 |

| ROPs | 0 | 24 |

| Tensor Cores | Not recorded | 312 |

| Pixel Rate | 0 MPixel/s | 47.52 GPixel/s |

| Texture Rate | 2,553.6 GTexel/s | 617.8 GTexel/s |

| FP32 | 81.72 TFLOPS | 39.54 TFLOPS |

| FP16 | 81.72 TFLOPS (1:1) | 79.07 TFLOPS (2:1) |

| TDP | 750 W | 500 W |

| Slot Width | OAM Module | SXM Module |

| Suggested PSU | 1150 W | 900 W |

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

| Display Outputs | No outputs | No outputs |

| Release Date | 2023-12-05 | 2024-01-31 |

| Production Status | Not recorded | Active |

The release dates differ by roughly two months, with the MI308X appearing in December 2023 and the H20 in January 2024. The H20 has an active production status, while the MI308X's status is not recorded. The H20 lists a predecessor (Server Ada) and successor (Server Blackwell), while the MI308X lists only a predecessor (Radeon Instinct). Neither part has a launch MSRP recorded, so no pricing comparison is possible from the database.

Both parts share the same PCIe 5.0 x16 interface, the same HBM3 memory type, and the same 5 nm TSMC process. They also share the absence of display outputs and graphics API support. The fundamental differences are in compute scale, memory capacity, and power envelope. The MI308X is built for maximum memory footprint and FP32 throughput. The H20 is built for higher clock operation at lower power with a denser tensor core implementation for FP16 workloads.