AMD Instinct MI325X vs AMD Radeon Instinct MI308X Comparison

Head-to-Head Benchmarks

The recorded database contains no benchmark scores for either the AMD Instinct MI325X or the AMD Radeon Instinct MI308X. Both accelerators return an average benchmark score of zero, and the head-to-head benchmark comparison list is empty. Consequently, there are no measured performance deltas, no percentile shifts, and no raw scores to compare. The absence of data is itself informative: neither part has been exercised by the benchmark suite recorded in this database, so any quantitative performance ranking between the two cannot be established from the available measurements.

Both units sit at the 50th percentile among all GPUs in the database, a neutral placement that reflects the lack of recorded benchmark submissions rather than a measured performance tier. The wins counter shows zero wins for each accelerator, which aligns with the empty benchmark array. Without benchmark results, the head-to-head comparison defaults to a specification-level analysis, where the two accelerators share identical compute resources but diverge sharply in memory configuration and power envelope.

The only quantitative performance figures available are theoretical peak rates drawn from the specification fields. Both accelerators list a texture rate of 2,553.6 GTexel/s and an FP32 throughput of 81.72 TFLOPS, confirming identical shader array capability. The FP16 figures differ substantially: the MI325X lists 81.72 TFLOPS at a 1:1 ratio, while the MI308X lists 653.7 TFLOPS at an 8:1 ratio. That difference indicates the MI308X executes FP16 at eight times the FP32 rate, whereas the MI325X executes FP16 at the same rate as FP32. For mixed-precision workloads, the recorded data suggests the MI308X holds a theoretical 8x advantage in FP16 peak throughput, though no measured benchmark confirms this in practice.

FAQ

Q: Which accelerator has more memory capacity?

A: The AMD Instinct MI325X carries 256 GB of HBM3e memory, while the AMD Radeon Instinct MI308X carries 192 GB of HBM3. The MI325X leads by 64 GB.

Q: Do the two accelerators use the same graphics core?

A: Yes. Both list the Aqua Vanjaram chip, built on the CDNA 3.0 architecture, produced on TSMC's 5 nm process with 153,000 million transistors and a 1017 mm² die size.

Q: How does memory bandwidth compare between the two?

A: The MI308X records a memory bandwidth of 10.3 TB/s, which is higher than the MI325X's 6.14 TB/s. The MI308X also lists a higher effective memory clock of 10.1 Gbps versus 6 Gbps for the MI325X, despite the MI325X using HBM3e and the MI308X using HBM3.

Q: What is the power draw difference?

A: The MI325X has a TDP of 1000 W and a suggested PSU rating of 1400 W. The MI308X has a TDP of 750 W and a suggested PSU rating of 1150 W. The MI325X draws 250 W more under the recorded TDP figures.

Q: Are the compute core counts identical?

A: Yes. Both accelerators list 19,456 shading units, 1,216 texture mapping units, and 0 ROPs. The FP32 throughput is also identical at 81.72 TFLOPS.

Q: Which accelerator was released earlier?

A: The AMD Radeon Instinct MI308X has a release date of 2023-12-05, while the AMD Instinct MI325X has a release date of 2024-10-09. The MI308X precedes the MI325X by roughly ten months.

Where Each One Wins

The AMD Instinct MI325X wins on memory capacity. Its 256 GB HBM3e pool exceeds the MI308X's 192 GB HBM3 allocation by 64 GB, which suits workloads where model or dataset size exceeds the smaller frame buffer. It also carries a more recent release date, arriving in October 2024 versus December 2023 for the MI308X, and lists HBM3e as its memory type, a newer generation than the MI308X's HBM3.

The AMD Radeon Instinct MI308X wins on memory bandwidth and FP16 peak throughput. Its 10.3 TB/s bandwidth is 4.16 TB/s higher than the MI325X's 6.14 TB/s, a 68% advantage in raw memory throughput. Its FP16 figure of 653.7 TFLOPS at an 8:1 ratio dwarfs the MI325X's 81.72 TFLOPS at a 1:1 ratio, giving the MI308X an eightfold theoretical advantage in half-precision arithmetic. The MI308X also consumes less power, at 750 W TDP versus 1000 W for the MI325X, and requires a smaller suggested PSU at 1150 W versus 1400 W.

Neither accelerator has any recorded benchmark wins, so these distinctions rest entirely on specification fields rather than measured performance. The MI325X suits capacity-bound memory scenarios; the MI308X suits bandwidth-bound and FP16-heavy scenarios.

Specification Differences

The two accelerators differ in the following recorded fields:

• Memory size: MI325X 256 GB HBM3e, MI308X 192 GB HBM3
• Memory clock: MI325X 1500 MHz, 6 Gbps effective; MI308X 2525 MHz, 10.1 Gbps effective
• Memory bandwidth: MI325X 6.14 TB/s, MI308X 10.3 TB/s
• FP16 throughput: MI325X 81.72 TFLOPS (1:1), MI308X 653.7 TFLOPS (8:1)
• TDP: MI325X 1000 W, MI308X 750 W
• Suggested PSU: MI325X 1400 W, MI308X 1150 W
• Release date: MI325X 2024-10-09, MI308X 2023-12-05
• Generation label: MI325X listed under "Instinct (MIx)", MI308X listed under "Radeon Instinct (MIx)"
• Predecessor: MI325X lists Radeon Instinct, MI308X lists FirePro Data Center
• API support: MI325X lists DirectX, OpenGL, and Vulkan as N/A; MI308X lists null values for these fields

All other specification fields match exactly: base clock 1000 MHz, boost clock 2100 MHz, 8192-bit memory bus, 19,456 shading units, 1,216 TMUs, 0 ROPs, 2,553.6 GTexel/s texture rate, 0 MPixel/s pixel rate, 81.72 TFLOPS FP32, PCIe 5.0 x16 bus interface, OAM Module slot width, no display outputs, no power connectors, 5 nm TSMC process, 153,000 million transistors, 1017 mm² die size, and 150.4M transistors per mm² density.

Architecture Differences

Both accelerators share the same underlying architecture. The chip is Aqua Vanjaram on the CDNA 3.0 architecture, fabricated by TSMC on a 5 nm process. Transistor count is identical at 153,000 million, and die size is identical at 1017 mm², yielding the same transistor density of 150.4M per mm². The compute array is also identical: 19,456 shading units and 1,216 TMUs in both parts, with no ROPs, no ray tracing cores, and no tensor cores listed.

The architectural divergence appears in the memory subsystem and the FP16 execution path. The MI325X uses HBM3e memory with a 256 GB capacity and a 6.14 TB/s bandwidth, while the MI308X uses HBM3 memory with a 192 GB capacity and a 10.3 TB/s bandwidth. Both share an 8192-bit memory bus, so the bandwidth difference stems from the higher effective memory clock on the MI308X (10.1 Gbps versus 6 Gbps). The FP16 path differs in ratio: the MI325X executes FP16 at a 1:1 ratio to FP32 (81.72 TFLOPS each), while the MI308X executes FP16 at an 8:1 ratio (653.7 TFLOPS FP16 versus 81.72 TFLOPS FP32). This indicates the MI308X dedicates additional hardware throughput to half-precision operations, while the MI325X treats FP16 and FP32 at parity.

The API support fields also differ: the MI325X explicitly lists DirectX, OpenGL, and Vulkan as N/A, while the MI308X records null values for the same fields, suggesting no display or graphics API exposure for either part, consistent with their OAM Module form factor and lack of display outputs.

The Verdict

The data indicates a clear split: the AMD Instinct MI325X is the capacity-oriented accelerator, and the AMD Radeon Instinct MI308X is the bandwidth and half-precision oriented accelerator. For workloads that require fitting larger working sets into on-board memory, the MI325X's 256 GB HBM3e pool provides 64 GB more capacity than the MI308X's 192 GB HBM3. For workloads that stress memory throughput or FP16 arithmetic, the MI308X leads with 10.3 TB/s bandwidth versus 6.14 TB/s, and 653.7 TFLOPS FP16 versus 81.72 TFLOPS.

Power consumption favors the MI308X as well, with a 750 W TDP and 1150 W suggested PSU versus the MI325X's 1000 W TDP and 1400 W suggested PSU. The MI308X delivers higher memory bandwidth and higher FP16 peak throughput while drawing 250 W less, according to the recorded specifications. However, it does so with 64 GB less memory and an older HBM3 memory type.

The MI325X compensates with a newer release date and a larger memory footprint, but it offers no measured performance advantage in the database, as both parts have zero benchmark scores. The compute core configuration is identical between the two, so raw FP32 throughput, texture rate, and shading unit counts do not differentiate them. The choice rests on memory profile and power envelope: the MI325X for larger memory capacity at higher power, the MI308X for higher bandwidth and FP16 throughput at lower power. Without benchmark measurements, these specification-driven conclusions are the only defensible positions the database supports.