AMD Instinct MI325X vs AMD Radeon Instinct MI300X Comparison

The Verdict

The AMD Instinct MI325X and AMD Radeon Instinct MI300X share the same foundational silicon, the Aqua Vanjaram chip, built on CDNA 3.0 architecture at TSMC's 5 nm node. Both cards deliver identical compute throughput in FP32 at 81.72 TFLOPS, identical texture rates at 2,553.6 GTexel/s, and identical shading unit and TMU counts. The recorded data shows the MI325X is the newer accelerator, released on 2024-10-09, while the MI300X launched on 2023-12-05. The decisive differences lie in memory configuration, power envelope, and FP16 throughput.

The MI325X uses 256 GB of HBM3e memory with a 6.14 TB/s bandwidth, while the MI300X uses 192 GB of HBM3 with a 10.3 TB/s bandwidth. The MI325X carries a 1000 W TDP and suggests a 1400 W PSU, whereas the MI300X runs at 750 W TDP with a 1150 W suggested PSU. The MI325X records FP16 performance at 81.72 TFLOPS (1:1), while the MI300X records FP16 performance at 653.7 TFLOPS (8:1). The MI325X is the choice for larger memory capacity, the MI300X for higher memory bandwidth and FP16 compute density. Both occupy the same OAM Module slot format and use PCIe 5.0 x16.

FAQ

Q: Which accelerator has more memory capacity?

A: The AMD Instinct MI325X has 256 GB of HBM3e memory, while the AMD Radeon Instinct MI300X has 192 GB of HBM3 memory. The MI325X provides 64 GB more capacity.

Q: Which accelerator has higher memory bandwidth?

A: The AMD Radeon Instinct MI300X has a memory bandwidth of 10.3 TB/s, compared to 6.14 TB/s for the AMD Instinct MI325X. The MI300X delivers higher bandwidth despite its smaller capacity.

Q: Do the two accelerators have the same compute performance?

A: Yes, in FP32 both deliver 81.72 TFLOPS. In FP16, the MI300X records 653.7 TFLOPS (8:1), whereas the MI325X records 81.72 TFLOPS (1:1). The MI300X has a much higher FP16 peak rate under the 8:1 ratio.

Q: What are the power requirements for each card?

A: The MI325X has a TDP of 1000 W and a suggested PSU of 1400 W. The MI300X has a TDP of 750 W and a suggested PSU of 1150 W.

Q: Are the chips and architecture identical?

A: Yes, both use the Aqua Vanjaram chip with CDNA 3.0 architecture, TSMC 5 nm process, 153,000 million transistors, and a 1017 mm² die size.

Q: What is the memory clock for each?

A: The MI325X memory clock is 1500 MHz with 6 Gbps effective, while the MI300X memory clock is 2525 MHz with 10.1 Gbps effective.

Architecture Differences

Both accelerators share the Aqua Vanjaram chip and CDNA 3.0 architecture, fabricated on TSMC's 5 nm process. The transistor count is identical at 153,000 million, and the die size is identical at 1017 mm². The transistor density is 150.4M per mm² for both. The shading unit count is 19456 for each, and the TMU count is 1216 for each. Neither card has ROPs, with pixel rate recorded as 0 MPixel/s for both.

The architectural split appears in memory technology and compute ratios. The MI325X pairs its CDNA 3.0 design with HBM3e memory, while the MI300X uses HBM3. The FP16 ratio differs: the MI325X records 1:1 FP16 relative to FP32, while the MI300X records 8:1 FP16. This indicates the MI300X uses a denser FP16 path, reaching 653.7 TFLOPS, while the MI325X keeps FP16 at the same level as FP32 at 81.72 TFLOPS.

Both cards use PCIe 5.0 x16 as the bus interface and have no display outputs. Neither card lists DirectX, OpenGL, or Vulkan API support in the database, with the MI325X explicitly marked N/A for all three. The MI325X generation is listed as Instinct (MIx), while the MI300X generation is listed as Radeon Instinct (MIx). The MI325X predecessor is Radeon Instinct, and the MI300X predecessor is FirePro Data Center.

Specification Differences

The recorded data shows these fields differ between the two accelerators:

• Memory size: MI325X has 256 GB HBM3e, MI300X has 192 GB HBM3.
• Memory type: HBM3e for the MI325X, HBM3 for the MI300X.
• Memory clock: 1500 MHz (6 Gbps effective) for the MI325X, 2525 MHz (10.1 Gbps effective) for the MI300X.
• Memory bandwidth: 6.14 TB/s for the MI325X, 10.3 TB/s for the MI300X.
• FP16 performance: 81.72 TFLOPS (1:1) for the MI325X, 653.7 TFLOPS (8:1) for the MI300X.
• TDP: 1000 W for the MI325X, 750 W for the MI300X.
• Suggested PSU: 1400 W for the MI325X, 1150 W for the MI300X.
• Release date: 2024-10-09 for the MI325X, 2023-12-05 for the MI300X.
• Predecessor: Radeon Instinct for the MI325X, FirePro Data Center for the MI300X.
• Generation label: Instinct (MIx) for the MI325X, Radeon Instinct (MIx) for the MI300X.

Fields that remain identical include base clock at 1000 MHz, boost clock at 2100 MHz, FP32 at 81.72 TFLOPS, texture rate at 2,553.6 GTexel/s, shading units at 19456, TMUs at 1216, ROPs at 0, bus interface at PCIe 5.0 x16, slot width at OAM Module, power connectors as none, display outputs as none, and the full chip-level set of process node, foundry, transistors, die size, and transistor density.

Head-to-Head Benchmarks

The database contains no recorded benchmark scores for either accelerator. The avgBenchmarkScore is 0 for both, and both sit at the 50th percentile versus all GPUs. The headToHeadBenchmarks array is empty, and winsA and winsB are both 0. Without measured benchmark data, the comparison rests on the recorded specification differences.

The clearest win for the MI325X is memory capacity. It offers 256 GB versus 192 GB, a 64 GB advantage. This directly supports larger model footprints or higher-capacity datasets resident on the accelerator. The MI325X also uses HBM3e, which is the newer memory generation in the recorded data, though the bandwidth figure is lower at 6.14 TB/s compared to 10.3 TB/s.

The clearest win for the MI300X is memory bandwidth. At 10.3 TB/s, it exceeds the MI325X by 4.16 TB/s, a substantial margin of about 68% over the MI325X figure. The MI300X also records a much higher FP16 peak at 653.7 TFLOPS under the 8:1 ratio, which is 8 times the MI325X FP16 figure of 81.72 TFLOPS. The MI300X has a lower TDP at 750 W versus 1000 W, and a lower suggested PSU at 1150 W versus 1400 W.

Both cards share identical FP32 compute at 81.72 TFLOPS, identical texture rate at 2,553.6 GTexel/s, identical boost clock at 2100 MHz, and identical base clock at 1000 MHz. The MI325X memory clock is lower at 1500 MHz effective 6 Gbps, while the MI300X memory clock is higher at 2525 MHz effective 10.1 Gbps.

Where Each One Wins

The MI325X wins on capacity and memory generation. Its 256 GB HBM3e configuration is the larger memory pool in this comparison, and it uses the newer HBM3e type. The MI325X is also the more recent release, dated 2024-10-09, which may indicate a later product cycle in the database. Its 1000 W TDP and 1400 W suggested PSU reflect a higher power envelope, which aligns with its larger memory array.

The MI300X wins on bandwidth, FP16 throughput, and power efficiency. Its 10.3 TB/s bandwidth is the highest recorded figure in this comparison, and its 653.7 TFLOPS FP16 (8:1) is the highest compute figure recorded for either card. The 750 W TDP and 1150 W suggested PSU are both lower than the MI325X figures, indicating a lower power draw for the same FP32 compute level.

For workloads that depend on FP32 compute, both cards are equivalent at 81.72 TFLOPS, so the choice would not shift on that metric. For workloads that depend on large memory capacity, such as holding very large model weights or datasets, the MI325X has the advantage with 256 GB. For workloads that depend on memory bandwidth or FP16 throughput, the MI300X has the advantage with 10.3 TB/s and 653.7 TFLOPS.

The MI325X fits deployments prioritizing memory size and HBM3e technology. The MI300X fits deployments prioritizing data movement speed, FP16 compute density, and lower power requirements. Both cards share the same OAM Module form factor, PCIe 5.0 x16 interface, and identical chip-level specifications, so platform integration requirements are similar aside from power delivery.