AMD Instinct MI300X vs NVIDIA B300 Comparison

FAQ

Q: How does the AMD Instinct MI300X compare to the NVIDIA B300 in raw compute performance?

A: The MI300X delivers 81.72 TFLOPS FP32 and 81.72 TFLOPS FP16 (1:1 ratio). The B300 delivers 76.99 TFLOPS FP32 and 1,231.8 TFLOPS FP16 (16:1 ratio). For FP32 workloads, the MI300X holds a 6.1% advantage, while the B300 has a massive 15.1x advantage in FP16 throughput, though that FP16 figure is achieved through a 16:1 ratio architecture.

Q: What is the memory capacity and bandwidth difference?

A: The MI300X has 192 GB of HBM3 with an 8192-bit bus and 5.32 TB/s bandwidth. The B300 has 144 GB of HBM3e with a 4096-bit bus and 4.10 TB/s bandwidth. The MI300X offers 33.3% more capacity and 29.8% more bandwidth.

Q: What is the recorded benchmark performance for each GPU?

A: The MI300X has a Geekbench OpenCL score of 317,994, placing it in the 100th percentile of all GPUs. The B300 has no recorded benchmark scores in the database, with an average benchmark score of 0 and a 50th percentile ranking.

Q: How does the MI300X compare to its nearest rivals in the database?

A: The MI300X trails the NVIDIA B200 by 8% (B200 scores 345,482), trails the NVIDIA H200 NVL by 5% (H200 scores 334,891), beats the NVIDIA L40S by 7.5% (L40S scores 295,763), and beats the NVIDIA RTX 6000 Ada Generation by 10.7% (RTX 6000 Ada scores 287,237).

Q: What are the power requirements for each module?

A: The MI300X has a 750 W TDP and a suggested PSU of 1150 W. The B300 has a 1400 W TDP and a suggested PSU of 1800 W. The B300 requires 86.7% more power according to TDP figures.

Q: What is the production status and release timeline for each?

A: The MI300X was released on December 5, 2023, with its production status not specified. The B300 was released on September 10, 2025, and is listed as Active in production, with its successor identified as Server Rubin.

The Verdict

The data presents an unusual comparison because the two accelerators occupy different positions in the benchmark database. The MI300X has an actual measured Geekbench OpenCL score of 317,994, placing it at the 100th percentile of all GPUs. The B300 has no recorded benchmark results, sitting at the 50th percentile with an average score of zero. Any direct performance verdict must account for this asymmetry: the MI300X is a proven quantity in the database, while the B300's capabilities are represented only through its specifications.

For FP32 compute workloads, the MI300X is the data-backed choice. Its 81.72 TFLOPS exceeds the B300's 76.99 TFLOPS, and its 192 GB memory capacity with 5.32 TB/s bandwidth provides a substantial buffer for large model residency. The MI300X also sits comfortably in a competitive position relative to its nearest rivals: 7.5% ahead of the L40S and 10.7% ahead of the RTX 6000 Ada Generation, though 5% behind the H200 NVL and 8% behind the B200.

For FP16 workloads, the B300's specification sheet is remarkable. Its 1,231.8 TFLOPS FP16 figure dwarfs the MI300X's 81.72 TFLOPS, though this comes with a 16:1 ratio that indicates a fundamentally different compute path. The B300 also carries a significantly higher power envelope at 1400 W TDP versus 750 W, and it is the only one of the two with explicit production status as Active.

Buyers needing a validated, immediately deployable accelerator with existing benchmark data should look to the MI300X. Buyers planning around the B300's specifications must accept that no measured performance data exists in the database yet, and that its 1400 W TDP demands substantially more power infrastructure.

Head-to-Head Benchmarks

The database contains no direct head-to-head benchmark results between the MI300X and B300. The MI300X carries a single Geekbench OpenCL score of 317,994, while the B300 has none. To contextualize the MI300X's result, the nearest rival data provides reference points: the NVIDIA B200 scores 345,482, which is 8% higher than the MI300X; the H200 NVL scores 334,891, which is 5% higher; the L40S scores 295,763, which is 7.5% lower; and the RTX 6000 Ada Generation scores 287,237, which is 10.7% lower.

The specification comparison offers the only quantitative head-to-head elsewhere. In FP32 throughput, the MI300X is 6.1% ahead of the B300. In texture rate, the MI300X delivers 2,553.6 GTexel/s versus 1,202.9 GTexel/s, a 112.3% advantage. The MI300X also leads in memory bandwidth by 29.8% and memory capacity by 33.3%. The B300 counters with a 15.1x FP16 throughput advantage, a pixel rate of 48.77 GPixel/s versus the MI300X's 0 MPixel/s, and higher base and boost clocks at 1665 MHz and 2032 MHz respectively, compared to 1000 MHz and 2100 MHz for the MI300X.

The MI300X's FP32 lead is modest but consistent with its higher shading unit count: 19,456 versus 18,944. Its texture unit count of 1,216 is more than double the B300's 592. The B300 includes 24 ROPs and 592 tensor cores, while the MI300X lists zero ROPs and no tensor core count.

Specification Differences

The two accelerators differ across nearly every measured specification. The MI300X uses an 8192-bit memory bus, the B300 uses a 4096-bit bus. Memory type differs: HBM3 on the MI300X, HBM3e on the B300. The MI300X carries 192 GB, the B300 carries 144 GB. Bandwidth is 5.32 TB/s versus 4.10 TB/s.

Compute resources diverge sharply. The MI300X has 19,456 shading units, 1,216 TMUs, and 0 ROPs. The B300 has 18,944 shading units, 592 TMUs, and 24 ROPs. Pixel rate is 0 MPixel/s on the MI300X versus 48.77 GPixel/s on the B300. Texture rate is 2,553.6 GTexel/s versus 1,202.9 GTexel/s. FP32 is 81.72 TFLOPS versus 76.99 TFLOPS. FP16 is 81.72 TFLOPS (1:1) versus 1,231.8 TFLOPS (16:1).

Clock speeds differ: base clock is 1000 MHz on the MI300X and 1665 MHz on the B300; boost clock is 2100 MHz versus 2032 MHz. Memory clock is 1300 MHz with 5.2 Gbps effective on the MI300X, versus 2000 MHz with 8 Gbps effective on the B300.

Power and physical specifications differ substantially. TDP is 750 W for the MI300X and 1400 W for the B300. Suggested PSU is 1150 W versus 1800 W. The MI300X is an OAM Module, the B300 is an SXM Module. Neither has display outputs. Both use PCIe 5.0 x16. The MI300X lists no power connectors, the B300's power connector field is empty.

The MI300X has no API support listed (DirectX N/A, OpenGL N/A, Vulkan N/A). The B300's API fields are all null.

Architecture Differences

The MI300X uses the Aqua Vanjaram chip built on CDNA 3.0 architecture, manufactured on a 5 nm process at TSMC. It contains 153,000 million transistors on a 1017 mm² die, yielding a transistor density of 150.4M per mm². The B300 uses the GB110 chip built on Blackwell Ultra architecture, also on a 5 nm TSMC process, with 104,000 million transistors. The B300's die size and transistor density are not recorded.

The MI300X's transistor count is 47.1% higher than the B300's. This aligns with its larger memory subsystem and wider 8192-bit bus. The B300 compensates with a higher base clock of 1665 MHz versus 1000 MHz, suggesting a different design philosophy: fewer transistors, higher frequency, and a narrower but faster memory interface.

The MI300X belongs to the Instinct (MIx) generation with Radeon Instinct as its predecessor. The B300 belongs to the Server Blackwell (Bxx) generation with Server Hopper as its predecessor and Server Rubin as its successor. The B300's production status is Active; the MI300X's production status is not recorded.

The FP16 ratio difference is the most telling architectural divergence. The MI300X's 1:1 FP16 ratio means it treats FP16 and FP32 with equal throughput. The B300's 16:1 ratio indicates a tensor-heavy design where FP16 compute is massively parallelized, likely through its 592 tensor cores. The MI300X lists no tensor cores and no RT cores. The B300 also lists no RT cores but does list tensor cores.

Where Each One Wins

The MI300X wins in scenarios requiring large memory capacity and high bandwidth. Its 192 GB HBM3 pool with 5.32 TB/s bandwidth exceeds the B300's 144 GB HBM3e with 4.10 TB/s by 33.3% and 29.8% respectively. Workloads that require holding large models or datasets entirely in GPU memory will favor the MI300X. Its 8192-bit bus is the widest recorded in this comparison, and its texture rate of 2,553.6 GTexel/s is 112.3% higher.

The MI300X also wins in FP32 compute. At 81.72 TFLOPS, it is 6.1% ahead of the B300's 76.99 TFLOPS. The database shows it performs strongly against its rivals: 7.5% ahead of the L40S and 10.7% ahead of the RTX 6000 Ada Generation, while sitting 5% and 8% behind the H200 NVL and B200 respectively. Its 100th percentile ranking among all GPUs confirms elite standing.

The B300 wins in FP16 compute by an enormous margin. Its 1,231.8 TFLOPS versus the MI300X's 81.72 TFLOPS is a 15.1x difference. Applications that can leverage the 16:1 ratio and 592 tensor cores will see substantially higher throughput on the B300. Its 48.77 GPixel/s pixel rate versus 0 MPixel/s on the MI300X also gives it a clear edge in any rasterization-adjacent workload, though both are server accelerators with no display outputs.

The B300 has higher base and boost clocks (1665 MHz and 2032 MHz versus 1000 MHz and 2100 MHz), which may benefit latency-sensitive workloads despite the lower overall FP32 throughput. Its 24 ROPs provide some fixed-function output capability that the MI300X entirely lacks.

The power envelope splits these accelerators into different deployment classes. The B300's 1400 W TDP and 1800 W suggested PSU versus the MI300X's 750 W and 1150 W means the MI300X fits into denser power-constrained racks. The B300's Active production status indicates current availability, while the MI300X's status is unrecorded.

The B300's FP16 capability, tensor cores, and newer release date (September 10, 2025 versus December 5, 2023) point toward AI inference and training workloads where reduced precision is standard. The MI300X's validated benchmark score, larger memory, and lower power draw point toward FP32 simulation, large-model inference, and environments where the power infrastructure cannot support 1400 W modules.