AMD Instinct MI308X vs NVIDIA B300 SXM6 AC Comparison

Head-to-Head Benchmarks

The recorded data includes a single benchmark score for the NVIDIA B300 SXM6 AC, while the AMD Instinct MI308X has no benchmark entries in the database. The B300 SXM6 AC achieved a Geekbench OpenCL score of 369,831, which places it at the 100th percentile among all GPUs. This means the B300 SXM6 AC sits at the absolute top of the recorded performance distribution, a position no other GPU in the database currently occupies.

The AMD Instinct MI308X, by contrast, has a percentile rank of 50 and an average benchmark score of 0, indicating that no measurable performance data has been logged for this part. As a result, direct head-to-head comparisons cannot be made from actual test runs. The database does, however, provide rival comparisons for the B300 SXM6 AC, which offer context for its standing. The B300 SXM6 AC outperforms the NVIDIA B200 by 7 percent, the NVIDIA H200 NVL by 10.4 percent, the AMD Instinct MI300X by 16.3 percent, and the NVIDIA L40S by 25 percent. These delta percentages are derived from the average scores of those rival parts, which are 345,482 for the B200, 334,891 for the H200 NVL, 317,994 for the MI300X, and 295,763 for the L40S.

The margin over the closest rival, the B200, is relatively modest at 7 percent, suggesting that within the same vendor family, performance gains are incremental. The gap widens when compared to the previous-generation H200 NVL, where the B300 SXM6 AC holds a 10.4 percent advantage. Against the AMD Instinct MI300X, the B300 SXM6 AC leads by 16.3 percent, a substantial margin that underscores the generational leap. The largest delta is against the L40S, a workstation-oriented part, at 25 percent. These figures indicate that the B300 SXM6 AC is not merely at the top of the database; it is meaningfully ahead of several established accelerators.

Because the MI308X has no recorded benchmark scores, the head-to-head section of the database is empty. The wins count for both parts stands at zero. The analysis must therefore rely on architectural specifications and the B300's measured performance against its named rivals.

Architecture Differences

The two accelerators differ fundamentally in architecture. The AMD Instinct MI308X uses the Aqua Vanjaram chip based on CDNA 3.0, while the NVIDIA B300 SXM6 AC uses the GB110 chip based on Blackwell Ultra. Both are manufactured on a 5 nm process at TSMC, but the transistor counts diverge sharply. The MI308X contains 153,000 million transistors on a die size of 1017 mm², yielding a transistor density of 150.4 million transistors per square millimeter. The B300 SXM6 AC contains 208,000 million transistors on a larger die of 1628 mm², resulting in a lower density of 127.8 million per square millimeter. The B300 thus packs 55,000 million more transistors, but spreads them over a die that is 611 mm² larger.

Memory configurations also differ. The MI308X uses 192 GB of HBM3 with an 8192-bit bus and 5.32 TB/s of bandwidth. The B300 SXM6 AC uses 288 GB of HBM3e, also on an 8192-bit bus, but with 8.19 TB/s of bandwidth. The B300 holds a 96 GB capacity advantage and delivers roughly 54 percent more memory bandwidth, a critical factor for large-model inference and training workloads.

Clock speeds show a different tradeoff. The MI308X has a base clock of 1000 MHz and a boost clock of 2100 MHz. The B300 SXM6 AC has a higher base clock of 1665 MHz but a lower boost clock of 2032 MHz. Memory clocks differ as well: the MI308X runs at 1300 MHz with 5.2 Gbps effective, while the B300 runs at 2000 MHz with 8 Gbps effective.

Compute resources are configured differently. The MI308X has 19,456 shading units, 1,216 texture mapping units, and zero ROPs, with a pixel rate of 0 MPixel/s and a texture rate of 2,553.6 GTexel/s. The B300 SXM6 AC has 18,944 shading units, 592 TMUs, and 24 ROPs, with a pixel rate of 48.77 GPixel/s and a texture rate of 1,202.9 GTexel/s. The MI308X has 512 more shading units and double the TMU count, but the B300 includes ROPs where the MI308X has none. The B300 also lists 592 tensor cores, while the MI308X lists none in the database.

Floating-point throughput is close. The MI308X delivers 81.72 TFLOPS for both FP32 and FP16 (1:1). The B300 SXM6 AC delivers 76.99 TFLOPS for both FP32 and FP16 (1:1). The MI308X holds a roughly 6 percent advantage in raw FP32 and FP16 peak rates, despite the B300's larger transistor budget.

Power and interface specifications differ considerably. The MI308X has a TDP of 750 W and a suggested PSU of 1150 W, while the B300 SXM6 AC has a TDP of 1100 W and a suggested PSU of 1500 W. The B300 consumes 350 W more. The MI308X uses an OAM Module slot width with no power connectors listed and a PCIe 5.0 x16 bus interface. The B300 uses an SXM Module slot width and a PCIe 6.0 x16 bus interface. Neither part has display outputs, and both list DirectX, OpenGL, and Vulkan as not applicable.

The B300 SXM6 AC has a production status of Active, while the MI308X has none recorded. Release dates differ by nearly two years: the MI308X launched on December 5, 2023, and the B300 SXM6 AC launched on September 10, 2025. The B300 lists a predecessor of Server Hopper and a successor of Server Rubin, while the MI308X lists a predecessor of Radeon Instinct and no successor.

Where Each One Wins

The AMD Instinct MI308X wins on raw shader throughput. With 19,456 shading units and a boost clock of 2100 MHz, it reaches 81.72 TFLOPS in FP32, which is 4.73 TFLOPS higher than the B300's 76.99 TFLOPS. Its texture rate of 2,553.6 GTexel/s is more than double the B300's 1,202.9 GTexel/s, and its transistor density of 150.4 million per square millimeter is higher. The MI308X also consumes less power, with a TDP of 750 W versus 1100 W for the B300, and its suggested PSU of 1150 W is 350 W lower. For workloads that are sensitive to FP32 throughput and texture operations, and where power draw is a constraint, the MI308X has the specification advantage.

The NVIDIA B300 SXM6 AC wins on memory capacity and bandwidth. Its 288 GB of HBM3e with 8.19 TB/s of bandwidth exceeds the MI308X's 192 GB of HBM3 with 5.32 TB/s. The difference in bandwidth is approximately 2.87 TB/s, which is substantial for memory-bound workloads such as large language model inference and training with huge batch sizes. The B300 also has 24 ROPs and a pixel rate of 48.77 GPixel/s, whereas the MI308X has no ROPs and a pixel rate of 0 MPixel/s. The B300 includes 592 tensor cores, making it the only one of the two with a dedicated tensor processing path recorded in the database.

The B300's measured benchmark result reinforces its standing. Its Geekbench OpenCL score of 369,831 places it at the 100th percentile, and its 7 percent lead over the B200 and 16.3 percent lead over the AMD Instinct MI300X demonstrate that it is the strongest recorded performer in its immediate competitive set. The MI308X, with no benchmark entries, cannot claim a measured performance win in the database.

The PCIe interface also favors the B300, which uses PCIe 6.0 x16 compared to the MI308X's PCIe 5.0 x16. This matters for systems where host-to-device transfer rates are a bottleneck. The B300's higher base clock of 1665 MHz versus 1000 MHz suggests better sustained performance at lower utilization.

FAQ

Q: What is the single benchmark score recorded for the NVIDIA B300 SXM6 AC?

A: The B300 SXM6 AC has a Geekbench OpenCL score of 369,831, which places it at the 100th percentile among all GPUs in the database.

Q: How does the B300 SXM6 AC compare to its closest rival, the NVIDIA B200?

A: The B300 SXM6 AC leads the B200 by 7 percent, with the B200 having an average score of 345,482.

Q: Does the AMD Instinct MI308X have any benchmark scores in the database?

A: No. The MI308X has an empty benchmarks array, an average benchmark score of 0, and a percentile rank of 50.

Q: Which accelerator has more memory bandwidth?

A: The NVIDIA B300 SXM6 AC has 8.19 TB/s from 288 GB of HBM3e, while the AMD Instinct MI308X has 5.32 TB/s from 192 GB of HBM3.

Q: Which accelerator has higher FP32 throughput?

A: The AMD Instinct MI308X reaches 81.72 TFLOPS in FP32, which is higher than the NVIDIA B300 SXM6 AC's 76.99 TFLOPS.

Q: What are the TDP ratings for the two parts?

A: The AMD Instinct MI308X has a TDP of 750 W with a suggested PSU of 1150 W. The NVIDIA B300 SXM6 AC has a TDP of 1100 W with a suggested PSU of 1500 W.

Specification Differences

The two accelerators differ across nearly every recorded specification. The MI308X uses the Aqua Vanjaram chip with CDNA 3.0 architecture, while the B300 SXM6 AC uses the GB110 chip with Blackwell Ultra architecture. Transistor count is 153,000 million for the MI308X versus 208,000 million for the B300. Die size is 1017 mm² for the MI308X and 1628 mm² for the B300. Transistor density is 150.4 million per square millimeter for the MI308X and 127.8 million for the B300.

Base clock is 1000 MHz for the MI308X and 1665 MHz for the B300. Boost clock is 2100 MHz for the MI308X and 2032 MHz for the B300. Memory clock is 1300 MHz with 5.2 Gbps effective for the MI308X and 2000 MHz with 8 Gbps effective for the B300. Memory size is 192 GB of HBM3 for the MI308X and 288 GB of HBM3e for the B300. Both use an 8192-bit bus, but bandwidth is 5.32 TB/s for the MI308X and 8.19 TB/s for the B300.

Shading units are 19,456 for the MI308X and 18,944 for the B300. TMUs are 1,216 for the MI308X and 592 for the B300. ROPs are 0 for the MI308X and 24 for the B300. Tensor cores are not listed for the MI308X and are 592 for the B300. Pixel rate is 0 MPixel/s for the MI308X and 48.77 GPixel/s for the B300. Texture rate is 2,553.6 GTexel/s for the MI308X and 1,202.9 GTexel/s for the B300. FP32 and FP16 are 81.72 TFLOPS for the MI308X and 76.99 TFLOPS for the B300.

TDP is 750 W for the MI308X and 1100 W for the B300. Slot width is OAM Module for the MI308X and SXM Module for the B300. The MI308X lists no power connectors, while the B300 has no power connector data. Suggested PSU is 1150 W for the MI308X and 1500 W for the B300. Bus interface is PCIe 5.0 x16 for the MI308X and PCIe 6.0 x16 for the B300. Neither has display outputs. Production status is not listed for the MI308X and is Active for the B300. Release date is December 5, 2023 for the MI308X and September 10, 2025 for the B300. The MI308X lists a predecessor of Radeon Instinct and no successor; the B300 lists a predecessor of Server Hopper and a successor of Server Rubin.