AMD Instinct MI325X vs NVIDIA H20 Comparison

Head-to-Head Benchmarks

The database contains no recorded benchmark scores for either the AMD Instinct MI325X or the NVIDIA H20. Both entries show an average benchmark score of zero and no entries in their head-to-head results. The absence of measured data means direct performance comparisons cannot be derived from recorded results. What the database does provide is a full specification profile for each accelerator, which allows for a structural comparison of their capabilities.

The AMD Instinct MI325X lists a FP32 throughput of 81.72 TFLOPS, which is more than double the NVIDIA H20's 39.54 TFLOPS. In FP16, the MI325X again records 81.72 TFLOPS with a 1:1 ratio, while the H20 reaches 79.07 TFLOPS using a 2:1 ratio. The MI325X is 3.3% ahead of the H20 in FP16 peak throughput, a narrow margin that suggests both accelerators can process half-precision workloads at a similar theoretical ceiling. The FP32 gap is far wider: the MI325X delivers 106.7% more FP32 compute than the H20, indicating a substantial advantage in workloads that rely on single-precision arithmetic.

Texture rate follows the same pattern. The MI325X records 2,553.6 GTexel/s, while the H20 achieves 617.8 GTexel/s. That puts the MI325X at roughly 4.1 times the texture throughput of the H20. Pixel rate tells a different story, the MI325X lists 0 MPixel/s, while the H20 records 47.52 GPixel/s. The MI325X has no ROP units listed, whereas the H20 includes 24 ROPs. This suggests the MI325X is not designed for rasterization output, while the H20 retains some traditional graphics pipeline capability, despite both cards having no display outputs.

Memory bandwidth strongly favors the MI325X. The AMD part lists 6.14 TB/s of bandwidth across an 8192-bit bus with HBM3e memory. The NVIDIA H20 provides 4.03 TB/s over a 6144-bit bus with HBM3. The MI325X delivers 52.4% more memory bandwidth than the H20. Capacity also diverges sharply: 256 GB versus 96 GB. The MI325X holds 166.7% more memory, a meaningful difference for models or datasets that exceed the H20's capacity ceiling.

Clock behavior is inverted between the two. The H20 has a higher base clock at 1830 MHz versus 1000 MHz for the MI325X, but the MI325X has a higher boost clock at 2100 MHz versus 1980 MHz. The H20 runs its memory at 1313 MHz with 5.3 Gbps effective, while the MI325X lists 1500 MHz with 6 Gbps effective. Power draw also differs substantially: the MI325X has a TDP of 1000 W, exactly double the H20's 500 W. The suggested power supply for the MI325X is 1400 W, while the H20 lists 900 W.

FAQ

Q: Which accelerator has more FP32 compute capacity?

A: The AMD Instinct MI325X records 81.72 TFLOPS FP32, more than double the NVIDIA H20's 39.54 TFLOPS. The MI325X holds a 106.7% advantage in single-precision throughput.

Q: How does memory capacity compare between the two?

A: The MI325X carries 256 GB of HBM3e, while the H20 carries 96 GB of HBM3. The MI325X provides 166.7% more memory capacity.

Q: Which card has higher memory bandwidth?

A: The MI325X lists 6.14 TB/s across an 8192-bit bus, while the H20 lists 4.03 TB/s across a 6144-bit bus. The MI325X is 52.4% higher in memory bandwidth.

Q: Do both cards support the same PCIe interface?

A: Yes, both list PCIe 5.0 x16 as their bus interface.

Q: Are there any differences in transistor count?

A: Yes, the MI325X uses 153,000 million transistors on a 1017 mm² die, while the H20 uses 80,000 million transistors on an 814 mm² die. The MI325X has 91.3% more transistors.

Q: What is the release date for each accelerator?

A: The NVIDIA H20 has a release date of 2024-01-31, and the AMD Instinct MI325X has a release date of 2024-10-09. The H20 was released earlier in the year.

The Verdict

The recorded data points to two different design objectives. The AMD Instinct MI325X leads in raw compute density, memory capacity, and memory bandwidth. Its FP32 throughput of 81.72 TFLOPS, FP16 throughput of 81.72 TFLOPS, 256 GB memory pool, and 6.14 TB/s bandwidth position it as a high-capacity compute accelerator. The NVIDIA H20 counters with a lower power envelope of 500 W, a higher base clock of 1830 MHz, and the only pixel output capability of the pair at 47.52 GPixel/s. The H20 also includes 312 tensor cores, a feature the MI325X does not list.

The percentile ranking for both is identical at 50, and both have an average benchmark score of zero, so the database does not favor either on measured performance. The selection between the two rests on workload characteristics. The MI325X is designed to handle large memory footprints and high-throughput FP32 or FP16 arithmetic. The H20 is a lower-power alternative with a smaller memory footprint, a higher base clock, and tensor core hardware. The MI325X uses more power and requires a larger suggested PSU, while the H20's lower TDP makes it the less demanding option in power-constrained environments.

Specification Differences

The two accelerators differ across nearly every major specification field. The MI325X uses the Aqua Vanjaram chip with CDNA 3.0 architecture, while the H20 uses the GH100 chip with Hopper architecture. The MI325X lists 19456 shading units, 1216 TMUs, and no ROPs. The H20 lists 9984 shading units, 312 TMUs, and 24 ROPs. The MI325X has no listed tensor cores, while the H20 has 312 tensor cores.

Memory configuration is a clear differentiator: the MI325X has 256 GB of HBM3e on an 8192-bit bus, while the H20 has 96 GB of HBM3 on a 6144-bit bus. Memory clocks also differ, with the MI325X at 1500 MHz (6 Gbps effective) and the H20 at 1313 MHz (5.3 Gbps effective). Bandwidth follows: 6.14 TB/s versus 4.03 TB/s.

Clock speeds are structured differently. The MI325X has a 1000 MHz base clock and a 2100 MHz boost clock. The H20 has a 1830 MHz base clock and a 1980 MHz boost clock. The MI325X has a higher boost, while the H20 has a much higher base.

Power specifications diverge sharply. The MI325X has a TDP of 1000 W and a suggested PSU of 1400 W, with no power connectors listed. The H20 has a TDP of 500 W and a suggested PSU of 900 W. Slot type also differs: the MI325X uses an OAM Module, while the H20 uses an SXM Module.

Transistor count and die size differ: 153,000 million transistors on 1017 mm² for the MI325X, 80,000 million on 814 mm² for the H20. Transistor density is 150.4M per mm² for the MI325X and 98.3M per mm² for the H20. The MI325X is fabricated on a 5 nm process at TSMC, as is the H20.

Release dates differ by roughly eight months: the H20 launched on 2024-01-31 and the MI325X on 2024-10-09. The H20 has a production status of Active, while the MI325X lists none. The H20 has a successor, Server Blackwell, while the MI325X lists no successor. The MI325X lists Radeon Instinct as its predecessor, while the H20 lists Server Ada.

Architecture Differences

The MI325X is built on CDNA 3.0, AMD's compute-focused architecture, while the H20 uses NVIDIA's Hopper architecture. Both are fabricated at TSMC on a 5 nm node, but the chips differ in scale. The MI325X packs 153,000 million transistors into a 1017 mm² die, resulting in a density of 150.4M transistors per mm². The H20 contains 80,000 million transistors on an 814 mm² die, with a density of 98.3M per mm². The MI325X uses 91.3% more transistors and occupies 24.9% more die area.

The MI325X has no ROPs listed, no pixel rate, and no graphics API support, a sign that it is tailored strictly for compute. The H20 retains 24 ROPs and a pixel rate of 47.52 GPixel/s, a sign that some graphics pipeline elements remain, even though display outputs are absent on both. Neither card lists DirectX, OpenGL, or Vulkan support, so the H20's ROPs do not translate into consumer graphics functionality.

Tensor capabilities differ. The H20 explicitly lists 312 tensor cores, while the MI325X has no tensor core count in the database. The MI325X instead relies on its shading units and TMUs for compute throughput. Its FP16 performance is rated at 1:1 with FP32, meaning the same 81.72 TFLOPS figure applies to both precisions. The H20 rates FP16 at 79.07 TFLOPS with a 2:1 ratio, indicating its FP16 throughput is double its FP32 throughput.

Memory technology differs by generation and width. The MI325X uses HBM3e with a 8192-bit bus, while the H20 uses HBM3 with a 6144-bit bus. The MI325X has 166.7% more memory capacity and 52.4% more bandwidth. The H20's memory clock of 1313 MHz is lower than the MI325X's 1500 MHz, but its base clock of 1830 MHz is 83% higher than the MI325X's 1000 MHz.

The H20 lists a successor (Server Blackwell), meaning its architecture generation is being phased toward replacement. The MI325X lists no successor, leaving its product line position open. The H20 also lists a production status of Active, while the MI325X does not. Both cards use PCIe 5.0 x16 and have no display outputs. Neither lists a launch MSRP in the database.

Where Each One Wins

The AMD Instinct MI325X wins in raw compute throughput. Its FP32 figure of 81.72 TFLOPS is more than double the H20's 39.54 TFLOPS, and its FP16 figure of 81.72 TFLOPS edges out the H20's 79.07 TFLOPS. Any workload that is arithmetic-bound, particularly in single-precision or half-precision formats, will see a theoretical ceiling more than twice as high on the MI325X in FP32 and slightly higher in FP16.

The MI325X also wins on memory. Its 256 GB capacity is nearly triple the H20's 96 GB, and its 6.14 TB/s bandwidth is 52.4% higher. Large language models, training runs with big batch sizes, or datasets that need to stay resident on the accelerator will fit more easily on the MI325X. The 8192-bit bus provides a wider path to memory, and HBM3e raises the effective speed.

The NVIDIA H20 wins on power efficiency per the recorded TDP. At 500 W, it draws half the power of the MI325X's 1000 W. The suggested PSU of 900 W versus 1400 W reinforces this difference. In a server chassis with strict power limits, the H20 allows more accelerators per node or lower cooling requirements.

The H20 also wins on base clock, listed at 1830 MHz versus 1000 MHz for the MI325X. While the MI325X has a higher boost clock of 2100 MHz versus 1980 MHz, the H20's base clock is 83% higher, which may translate to more consistent sustained performance at lower utilization levels. The H20's tensor cores at 312 provide a dedicated path for matrix operations, a feature the MI325X does not list.

The MI325X wins on transistor count and density: 153,000 million transistors at 150.4M per mm², versus 80,000 million at 98.3M per mm². This suggests a more complex compute pipeline, consistent with its higher shading unit count of 19456 versus 9984. The MI325X also has 1216 TMUs versus 312, giving it a 3.9x advantage in texture rate.

The H20 wins on pixel rate, 47.52 GPixel/s versus 0 MPixel/s, and on ROP count, 24 versus none. These fields are largely irrelevant for a compute accelerator with no display outputs, but they do indicate the H20 retains more of a traditional GPU raster pipeline. The MI325X is a pure compute device in the database's classification.

The release timeline favors the H20 for earlier availability. It launched on 2024-01-31, while the MI325X appeared on 2024-10-09. The H20 lists an Active production status and a successor, indicating an established product lifecycle. The MI325X lists no production status and no successor, leaving its roadmap undefined in the database.