AMD Instinct MI300 vs NVIDIA B300 SXM6 AC Comparison

FAQ

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

A: The NVIDIA B300 SXM6 AC has an average benchmark score of 369,831 in the Geekbench OpenCL test, placing it at the 100th percentile among all GPUs in the database.

Q: How does the B300 SXM6 AC compare to the AMD Instinct MI300 in benchmark performance?

A: The B300 SXM6 AC holds a significant performance advantage. It outscores the Instinct MI300 by a wide margin, and against the closest AMD rival listed, the MI300X, it is 16.3% ahead.

Q: What are the memory capacities of these two accelerators?

A: The AMD Instinct MI300 features 128 GB of HBM3 memory, while the NVIDIA B300 SXM6 AC features 288 GB of HBM3e memory.

Q: What is the difference in memory bandwidth between the two?

A: The AMD Instinct MI300 delivers 5.32 TB/s of bandwidth, whereas the NVIDIA B300 SXM6 AC delivers 8.19 TB/s, a substantial increase.

Q: What are the transistor counts for each chip?

A: The AMD Instinct MI300 uses 153,000 million transistors on a 1017 mm² die, while the NVIDIA B300 SXM6 AC uses 208,000 million transistors on a 1628 mm² die.

Q: What is the thermal design power for each?

A: The AMD Instinct MI300 has a TDP of 600 W, while the NVIDIA B300 SXM6 AC has a TDP of 1100 W.

Architecture Differences

The AMD Instinct MI300 and NVIDIA B300 SXM6 AC represent two distinct approaches to high-performance compute acceleration. The MI300 is built on the CDNA 3.0 architecture with the Aqua Vanjaram chip, while the B300 SXM6 AC uses the Blackwell Ultra architecture with the GB110 chip. Both are fabricated on a 5 nm process at TSMC, but the similarities end there.

The MI300 packs 153,000 million transistors into a 1017 mm² die, achieving a transistor density of 150.4M per mm². The B300 SXM6 AC is a much larger chip, with 208,000 million transistors across a 1628 mm² die, but its density is lower at 127.8M per mm². The larger physical area and higher transistor budget give the NVIDIA part more room for compute resources, particularly for tensor operations.

Clock behavior differs markedly. The MI300 runs at a 1000 MHz base clock and 1700 MHz boost, while the B300 SXM6 AC starts at 1665 MHz base and reaches 2032 MHz boost. This clock advantage compounds with the architectural differences, resulting in substantially higher peak throughput for the NVIDIA part.

Memory architecture is another key differentiator. The MI300 uses 128 GB of HBM3 with an 8192-bit bus, producing 5.32 TB/s of bandwidth. The B300 SXM6 AC uses 288 GB of HBM3e, also on an 8192-bit bus, but achieves 8.19 TB/s. The newer HBM3e standard and higher effective memory clock of 8 Gbps versus 5.2 Gbps explain the bandwidth gap. The NVIDIA part also has a higher memory clock at 2000 MHz versus 1300 MHz on the AMD side.

Shader and texture configurations diverge significantly. The MI300 has 14,080 shading units and 880 texture mapping units, while the B300 SXM6 AC has 18,944 shading units and 592 TMUs. The NVIDIA accelerator also includes 592 tensor cores and 24 ROPs, whereas the AMD part lists no tensor cores and zero ROPs. This gives the B300 a clear structural advantage in mixed-precision and rasterization-adjacent workloads, even though both are designed primarily for compute.

The B300 SXM6 AC also introduces a PCIe 6.0 x16 bus interface, while the MI300 uses PCIe 5.0 x16. Neither card has display outputs, and both expose no graphics APIs, confirming their server-oriented design. The NVIDIA part is an SXM module, whereas the MI300 is a 267 mm long, 111 mm tall card that requires two 8-pin power connectors.

Where Each One Wins

The recorded data points to a clear split in workload suitability. The NVIDIA B300 SXM6 AC dominates in raw compute throughput, memory capacity, and memory bandwidth. Its 76.99 TFLOPS FP32 and FP16 performance is far ahead of the MI300's 47.87 TFLOPS for both precision levels. This makes the B300 the stronger choice for large-scale training runs, dense matrix operations, and workloads that can exploit its 288 GB memory pool.

The B300's 8.19 TB/s bandwidth is a decisive advantage for memory-bound kernels. Large language model inference, scientific simulations, and data analytics that repeatedly sweep through model weights will benefit from the higher sustained data movement. The 25% delta over the NVIDIA L40S in the nearest rival list shows that even within NVIDIA's own lineup, the B300 is positioned at the top.

The AMD Instinct MI300 has no benchmark entries in the database, and its percentile sits at 50. This means there is no recorded performance data to establish where it wins in practice. From the specification sheet alone, the MI300's lower TDP of 600 W versus 1100 W suggests it may be easier to integrate into existing power-constrained systems, but the database does not contain efficiency measurements to confirm this.

Texture rate is one area where the AMD part shows a nominal advantage: 1,496.0 GTexel/s versus 1,202.9 GTexel/s for the NVIDIA part. This could matter for workloads with heavy texture sampling, though both cards are compute-focused and lack display outputs. In every other measurable dimension, the B300 SXM6 AC is ahead.

Specification Differences

The two accelerators differ across nearly every specification field. The AMD Instinct MI300 uses the CDNA 3.0 architecture with the Aqua Vanjaram chip, while the NVIDIA B300 SXM6 AC uses Blackwell Ultra with the GB110 chip. The MI300 is from the Instinct (MIx) generation, while the B300 belongs to the Server Blackwell (Bxx) generation.

Transistor counts differ substantially: 153,000 million for AMD versus 208,000 million for NVIDIA. Die size also differs, with the MI300 at 1017 mm² and the B300 at 1628 mm². Transistor density is higher on the AMD chip at 150.4M per mm², versus 127.8M per mm² for NVIDIA.

Clock speeds favor NVIDIA. The MI300 has a 1000 MHz base and 1700 MHz boost, while the B300 has a 1665 MHz base and 2032 MHz boost. Memory clocks also differ: 1300 MHz with 5.2 Gbps effective for AMD, versus 2000 MHz with 8 Gbps effective for NVIDIA.

Memory capacity and type are different: 128 GB HBM3 for the MI300, 288 GB HBM3e for the B300. Bus width is identical at 8192 bit, but bandwidth is not: 5.32 TB/s versus 8.19 TB/s.

Compute resources differ. The MI300 has 14,080 shading units, 880 TMUs, zero ROPs, and no tensor cores. The B300 has 18,944 shading units, 592 TMUs, 24 ROPs, and 592 tensor cores. Pixel rate is 0 MPixel/s for AMD and 48.77 GPixel/s for NVIDIA. Texture rate is 1,496.0 GTexel/s for AMD and 1,202.9 GTexel/s for NVIDIA.

FP32 and FP16 throughput are both 47.87 TFLOPS for the MI300, while the B300 delivers 76.99 TFLOPS for both. TDP is 600 W for AMD and 1100 W for NVIDIA. The AMD card uses two 8-pin power connectors and suggests a 1000 W PSU; the NVIDIA SXM module has no listed power connectors and suggests a 1500 W PSU.

Bus interface differs: PCIe 5.0 x16 for AMD, PCIe 6.0 x16 for NVIDIA. Physical dimensions are only listed for the AMD card at 267 mm length and 111 mm height. The NVIDIA part is an SXM module with no listed dimensions. Release dates are January 3, 2023 for the MI300 and September 10, 2025 for the B300. The MI300's predecessor is Radeon Instinct, while the B300's predecessor is Server Hopper and its successor is Server Rubin. The B300 has an Active production status; the MI300 does not list one.

Head-to-Head Benchmarks

There are no direct head-to-head benchmark entries between the AMD Instinct MI300 and NVIDIA B300 SXM6 AC in the database. However, the comparison can be constructed through the B300's nearest rival list and the MI300's lack of recorded scores.

The B300 SXM6 AC achieves an average benchmark score of 369,831 in Geekbench OpenCL. Its nearest rivals show a clear hierarchy. The NVIDIA B200 scores 345,482, which is 7% behind the B300. The NVIDIA H200 NVL scores 334,891, 10.4% behind. The AMD Instinct MI300X scores 317,994, 16.3% behind. The NVIDIA L40S scores 295,763, 25% behind.

The AMD Instinct MI300 has no benchmark entries and an average score of zero, with a percentile of 50. The B300 sits at the 100th percentile. This means the MI300 cannot be directly positioned against the B300 using measured data. What is clear is that the B300 leads the field among its recorded rivals, and the MI300's closest sibling, the MI300X, is already 16.3% behind the B300.

The FP32 gap reinforces this. The B300 delivers 76.99 TFLOPS, which is 60.8% higher than the MI300's 47.87 TFLOPS. Memory bandwidth is 54% higher on the B300 (8.19 TB/s versus 5.32 TB/s). Memory capacity is 125% higher (288 GB versus 128 GB).

The B300's boost clock of 2032 MHz is 332 MHz higher than the MI300's 1700 MHz boost. Shader count is 4,864 units higher. Tensor cores, present only on the NVIDIA part, add 592 dedicated units for matrix operations. The MI300 has no tensor core count listed.

The only specification where the MI300 leads is texture rate, at 1,496.0 GTexel/s versus 1,202.9 GTexel/s for the B300. This is a 24.4% advantage for AMD. Transistor density is also higher on the MI300 at 150.4M per mm² versus 127.8M per mm², though this reflects the smaller die rather than a performance advantage.

The Verdict

The data points to the NVIDIA B300 SXM6 AC as the stronger accelerator across nearly every measurable dimension. Its 369,831 benchmark score places it at the 100th percentile, and it leads its nearest recorded rivals by 7% to 25%. Its FP32 throughput of 76.99 TFLOPS, memory capacity of 288 GB, and bandwidth of 8.19 TB/s make it the clear choice for compute-heavy workloads.

The AMD Instinct MI300 has no recorded benchmark scores, which makes direct comparison impossible. Its specifications place it well behind the B300 in compute throughput, memory capacity, and bandwidth. The MI300's lower TDP of 600 W and smaller physical footprint could matter for system integration, but the database does not include efficiency metrics to quantify this.

The B300's tensor cores, higher clock speeds, and 592 TMUs give it a structural edge in deep learning and mixed-precision work. The MI300's higher texture rate is a narrow advantage that does not offset the broader performance gap.

For buyers prioritizing raw compute and memory capacity, the B300 SXM6 AC is the data-supported choice. The MI300's role in the current landscape is less clear, as the lack of benchmark data leaves its practical performance unmeasured. The B300's 16.3% lead over the MI300X, its closest AMD rival, suggests that any AMD-based alternative would need to show exceptional efficiency or cost characteristics to compete, though those characteristics are not captured in this database.