AMD Instinct MI325X vs NVIDIA RTX A400 Comparison

Head-to-Head Benchmarks

The recorded data for the AMD Instinct MI325X contains no benchmark scores, while the NVIDIA RTX A400 has nine recorded measurements. This asymmetry defines the entire comparison. The MI325X sits at the 50th percentile among all GPUs in the database, whereas the RTX A400 sits at the 35th percentile. The MI325X has an average benchmark score of 0, meaning no standardized tests have been logged for it. The RTX A400, by contrast, posts an average benchmark score of 6078.

The RTX A400's strongest recorded result is in Geekbench OpenCL, where it scores 22844. Its Geekbench Vulkan result is close behind at 22237. These two scores indicate solid general-purpose compute performance for a small workstation card. The Passmark suite tells a different story about the same hardware. Passmark G3D gives the RTX A400 a score of 5983, while Passmark GPU Compute scores 2557. The gap between the Geekbench numbers and the Passmark numbers suggests workload-dependent behavior: the card handles OpenCL and Vulkan tasks far better than the specific DirectX tests in Passmark.

The DirectX results for the RTX A400 are notably low. Passmark DirectX 9 scores 87, DirectX 11 scores 37, DirectX 10 scores 32, and DirectX 12 scores 27. These numbers indicate that the card is not optimized for legacy or modern DirectX gaming workloads. The Passmark G2D score of 899 is comparatively stronger, showing that 2D desktop operations are not the bottleneck.

Since the MI325X has no recorded benchmarks, there are no head-to-head wins to report. The data cannot show which card is faster in any specific test. What the data does show is that the two products occupy entirely different segments of the GPU landscape. The MI325X is an accelerator with no display outputs, while the RTX A400 is a single-slot workstation card with four display outputs. Their benchmark profiles, where they exist, reflect those different purposes.

The absence of MI325X benchmark data is itself a finding. The database records a 50th percentile rank for the MI325X, but with no average score and no rivals listed, this percentile appears to be a placeholder rather than a measured value. The RTX A400, however, has a real percentile rank of 35, supported by a real average score of 6078.

FAQ

Q: Which GPU has the higher FP32 compute throughput?

A: The AMD Instinct MI325X delivers 81.72 TFLOPS FP32, while the NVIDIA RTX A400 delivers 2.706 TFLOPS FP32. The MI325X provides roughly 30 times the raw single-precision throughput.

Q: How do their memory subsystems compare?

A: The MI325X uses 256 GB of HBM3e memory on an 8192-bit bus, yielding 6.14 TB/s of bandwidth. The RTX A400 uses 4 GB of GDDR6 memory on a 64-bit bus, yielding 96.00 GB/s of bandwidth. The MI325X has 64 times the memory capacity and over 60 times the memory bandwidth.

Q: What is the RTX A400's closest rival in the database?

A: The nearest rival by average benchmark score is the NVIDIA GeForce MX230, which scores 6077 against the RTX A400's 6078, a delta of 0 percent. The NVIDIA Quadro P2000 scores 6049, a 0.5 percent difference, and the Intel Iris Pro Graphics 6200 scores 6117, a -0.6 percent difference.

Q: Does the MI325X support DirectX or Vulkan?

A: The database lists the MI325X's APIs as N/A for DirectX, OpenGL, and Vulkan. The RTX A400 supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4.

Q: What are the physical dimensions of the RTX A400?

A: The RTX A400 measures 163 mm (6.4 inches) in length and 69 mm (2.7 inches) in height. It is a single-slot card. The MI325X is an OAM module, and its dimensions are not recorded.

Q: How do the process nodes differ?

A: The MI325X is built on a 5 nm process at TSMC, while the RTX A400 is built on an 8 nm process at Samsung. The MI325X contains 153,000 million transistors on a 1017 mm² die, giving a transistor density of 150.4 million per mm². The RTX A400 contains 8,700 million transistors on a 200 mm² die, giving a density of 43.5 million per mm².

The Verdict

The data supports a clear division of roles. The AMD Instinct MI325X is an accelerator-class product: no display outputs, no API support for graphics, an OAM module form factor, and a 1000 W TDP. Its specifications point toward dense compute installations where memory capacity and bandwidth dominate. The NVIDIA RTX A400 is a workstation graphics card: single-slot, four mini-DisplayPort outputs, 50 W TDP, and full DirectX, OpenGL, and Vulkan support. Its benchmarks, modest as they are, confirm it functions as a working GPU for desktop and light compute tasks.

For users who require graphics output, the MI325X cannot serve that role at all. Its "No outputs" display configuration and N/A API support make it unsuitable for any workstation display workload. The RTX A400, with its 4x mini-DisplayPort 1.4a outputs and API support, is the only option here for rendering to a screen.

For users who require massive memory capacity, the RTX A400's 4 GB is insufficient, while the MI325X's 256 GB is in a different class entirely. The MI325X's 6.14 TB/s bandwidth and 8192-bit bus suggest it is built for large-scale inference, training, or scientific workloads. The RTX A400's 96.00 GB/s bandwidth and 64-bit bus place it at the entry level of workstation memory performance.

The RTX A400's benchmark scores show it competes with integrated graphics and older entry-level workstation cards. Its average score of 6078 places it alongside the GeForce MX230, Quadro P2000, Iris Pro Graphics 6200, and Radeon 760M, all within a 1 percent delta. The MI325X has no comparable benchmark data, so its actual performance in any measured workload remains unverified in the database.

Specification Differences

The two cards differ in nearly every recorded specification. The MI325X uses a 5 nm process at TSMC; the RTX A400 uses an 8 nm process at Samsung. Transistor counts diverge sharply: 153,000 million for the MI325X versus 8,700 million for the RTX A400. Die size is 1017 mm² versus 200 mm². Transistor density is 150.4 million per mm² versus 43.5 million per mm².

Clock speeds differ. The MI325X 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. Memory clocks are listed as 1500 MHz (6 Gbps effective) for the MI325X and 1500 MHz (12 Gbps effective) for the RTX A400.

Memory configurations are extreme opposites. The MI325X has 256 GB of HBM3e on an 8192-bit bus with 6.14 TB/s bandwidth. The RTX A400 has 4 GB of GDDR6 on a 64-bit bus with 96.00 GB/s bandwidth.

Compute unit counts differ by an order of magnitude. The MI325X has 19,456 shading units, 1,216 TMUs, and 0 ROPs. The RTX A400 has 768 shading units, 24 TMUs, and 16 ROPs. The RTX A400 also has 6 RT cores and 24 tensor cores; the MI325X lists no RT or tensor core counts.

Pixel and texture rates reflect their roles. The MI325X records 0 MPixel/s pixel rate and 2,553.6 GTexel/s texture rate. The RTX A400 records 28.19 GPixel/s pixel rate and 42.29 GTexel/s texture rate.

Power and physical specifications diverge completely. The MI325X has a TDP of 1000 W and no power connectors, with a suggested PSU of 1400 W. The RTX A400 has a TDP of 50 W, no power connectors, and a suggested PSU of 250 W. The MI325X is an OAM module; the RTX A400 is a single-slot card measuring 163 mm by 69 mm.

Bus interfaces differ: PCIe 5.0 x16 for the MI325X, PCIe 4.0 x8 for the RTX A400. Display outputs are absent on the MI325X, while the RTX A400 has 4x mini-DisplayPort 1.4a.

Architecture Differences

The MI325X uses the Aqua Vanjaram chip based on CDNA 3.0 architecture, belonging to the Instinct (MIx) generation. The RTX A400 uses the GA107 chip based on Ampere architecture, belonging to the Workstation Ampere (Ax000) generation. These are entirely different design philosophies: CDNA 3.0 targets matrix-heavy compute, while Ampere is a unified graphics and compute architecture.

The MI325X has no ROPs and no API support, indicating it is not designed for rasterization or graphics rendering at all. The RTX A400 has 16 ROPs, 6 RT cores, and 24 tensor cores, giving it hardware acceleration for ray tracing and tensor operations alongside traditional graphics.

The MI325X's predecessor is the Radeon Instinct, with no successor recorded. The RTX A400's predecessor is the Quadro Turing, and its successor is the Workstation Ada line. The RTX A400's production status is listed as Active; the MI325X's production status is not recorded.

Release dates place them close together: the MI325X launched on 2024-10-09, and the RTX A400 launched on 2024-04-15. Both are recent products, but the MI325X is built for a different scale of operation. Its 153,000 million transistors and 1017 mm² die represent an enormous investment in compute density, while the RTX A400's 8,700 million transistors and 200 mm² die represent an efficiency-focused design.

Where Each One Wins

The RTX A400 wins in any scenario requiring a display. Its 4x mini-DisplayPort 1.4a outputs, DirectX 12 Ultimate support, OpenGL 4.6, and Vulkan 1.4 make it a functional workstation card. Its 50 W TDP and single-slot form factor allow it to fit into small systems with modest power supplies. Its benchmark scores, particularly Geekbench OpenCL at 22844 and Geekbench Vulkan at 22237, show it handles compute APIs commonly used in desktop applications.

The MI325X wins in scenarios requiring massive memory capacity and bandwidth. Its 256 GB HBM3e pool at 6.14 TB/s is an order of magnitude beyond the RTX A400's 4 GB GDDR6 at 96.00 GB/s. Its FP32 throughput of 81.72 TFLOPS dwarfs the RTX A400's 2.706 TFLOPS. Its 2,553.6 GTexel/s texture rate indicates extreme fill-rate capability, though with 0 pixel rate and 0 ROPs, it cannot produce rendered frames.

The RTX A400's Passmark results show its limitations. DirectX 12 scores 27, DirectX 11 scores 37, and DirectX 10 scores 32, all indicating weak gaming performance. Its Passmark G3D score of 5983 and G2D score of 899 place it in entry-level territory. The MI325X has no such measurements, so no direct comparison is possible.

The data suggests the RTX A400 suits workstation users who need multi-display output, API compatibility, and low power draw. The MI325X suits compute environments where graphics are irrelevant and memory scale is paramount. Neither card competes in the other's domain, and the database records no overlapping benchmarks to suggest otherwise.