AMD Instinct MI308X vs NVIDIA B300 Comparison

# Where Each One Wins

The recorded data for the AMD Instinct MI308X and NVIDIA B300 shows a clear split in workload suitability, though neither part dominates across every category. The MI308X holds advantages in several raw throughput and capacity metrics that favor memory-bound and large-model inference workloads. The B300 counters with higher base clock speeds, a more recent production status, and a narrower but faster memory architecture.

On the AMD side, the Instinct MI308X uses a 8192 bit memory bus paired with 192 GB of HBM3 memory. This combination delivers 5.32 TB/s of bandwidth, which is 1.22 TB/s more than the B300's 4.10 TB/s. The larger memory capacity is a decisive factor for workloads that must hold very large models or datasets entirely on-device. The MI308X also leads in texture rate with 2,553.6 GTexel/s versus 1,202.9 GTexel/s for the B300, a 2.1x advantage that favors tasks with heavy texture sampling. The shading unit count is also higher on the MI308X at 19,456 versus 18,944, and the TMU count of 1,216 versus 592 gives the AMD part a 2.05x lead in texture mapping hardware.

The MI308X further leads in FP32 compute with 81.72 TFLOPS compared to 76.99 TFLOPS on the B300. That difference of 4.73 TFLOPS is modest in percentage terms, roughly 6.1% ahead, but it is still a measurable win for single-precision workloads. The transistor count also favors the AMD part, with 153,000 million transistors on a 1017 mm² die, versus 104,000 million transistors for the B300. The MI308X has a transistor density of 150.4M per mm², a figure not recorded for the B300.

On the NVIDIA side, the B300 wins on clock speeds. The base clock is 1665 MHz, which is 665 MHz higher than the MI308X's 1000 MHz. The boost clock is 2032 MHz, which is 68 MHz lower than the MI308X's 2100 MHz, so the AMD part still has the higher peak clock. The B300 has a faster effective memory clock at 8 Gbps versus 5.2 Gbps, though the narrower 4096 bit bus limits the resulting bandwidth. The B300 also supports FP16 at 1,231.8 TFLOPS with a 16:1 ratio, while the MI308X delivers 81.72 TFLOPS at 1:1. That is a massive 15.1x difference in favor of the B300 for FP16 tensor-heavy workloads, assuming the software can use the 16:1 path.

The B300 also has a pixel rate of 48.77 GPixel/s, while the MI308X records 0 MPixel/s, indicating the AMD part has no raster output stage in the measured configuration. The B300 includes 592 tensor cores and 24 ROPs, while the MI308X lists no tensor core or ROP count.

Both parts share a 5 nm process node from TSMC, PCIe 5.0 x16 bus interface, and no display outputs.

# The Verdict

The data points to two distinct deployment profiles. The AMD Instinct MI308X is the choice for capacity-first and bandwidth-first workloads. Its 192 GB of HBM3 memory, 5.32 TB/s bandwidth, and 2.1x texture rate advantage make it suited for large model residency and memory-intensive processing. The FP32 lead of 81.72 TFLOPS versus 76.99 TFLOPS also gives it a slight edge in general single-precision compute.

The NVIDIA B300 is the choice for FP16 throughput and clock-sensitive workloads. The 1,231.8 TFLOPS FP16 figure, delivered at a 16:1 ratio, dwarfs the MI308X's 81.72 TFLOPS at 1:1. For software stacks that leverage the B300's tensor core path, that is a 15.1x throughput advantage. The higher base clock of 1665 MHz versus 1000 MHz also favors latency-sensitive dispatch patterns. The B300 is the newer design, with a release date in September 2025 versus December 2023 for the MI308X, and it is listed as Active in production status while the MI308X has no production status recorded.

The B300's power envelope is larger at 1400 W TDP versus 750 W for the MI308X, and its suggested PSU is 1800 W versus 1150 W. The MI308X is an OAM module, while the B300 is an SXM module, so the physical integration path differs.

Neither part has benchmark scores recorded in the database. Both sit at the 50th percentile against all GPUs, and neither has nearest rivals listed. The head-to-head benchmark table is empty, so all conclusions here come from the specification-level data.

# Head-to-Head Benchmarks

No recorded benchmark scores exist for either GPU. The head-to-head benchmark dataset is empty, and the win counters for both parts are zero. The analysis therefore relies on the documented specification data.

The largest single-metric win for the AMD Instinct MI308X is in FP16 throughput, but only in the 1:1 configuration. The 81.72 TFLOPS figure matches its FP32 output exactly, indicating a 1:1 ratio. The B300's FP16 figure of 1,231.8 TFLOPS at a 16:1 ratio is a different implementation, and direct comparison requires knowing whether the workload uses the ratio path.

The largest straightforward specification win for the MI308X is memory bandwidth. The 5.32 TB/s figure is 29.8% higher than the B300's 4.10 TB/s. Memory capacity follows the same pattern: 192 GB versus 144 GB, a 33.3% advantage for the AMD part.

Texture rate is another dominant MI308X metric. At 2,553.6 GTexel/s, it is 112.3% higher than the B300's 1,202.9 GTexel/s. The TMU count of 1,216 versus 592 is a 105.4% advantage.

The B300's largest wins are in FP16 ratio throughput and pixel rate. The 1,231.8 TFLOPS FP16 figure is 15.1x the MI308X's 81.72 TFLOPS. The pixel rate of 48.77 GPixel/s versus 0 MPixel/s is a complete win for the B300, though the MI308X's zero value suggests the measurement does not apply to its architecture.

Clock speeds split between the two. The B300 has a 1665 MHz base clock, 66.5% higher than the MI308X's 1000 MHz. The MI308X has a 2100 MHz boost clock, 3.3% higher than the B300's 2032 MHz.

Power draw is not a performance metric, but the 1400 W TDP of the B300 versus 750 W for the MI308X is a substantial difference in operating envelope. The suggested PSU figures follow: 1800 W for the B300 versus 1150 W for the MI308X.

# FAQ

Q: Which GPU has more memory bandwidth?

A: The AMD Instinct MI308X delivers 5.32 TB/s over an 8192 bit bus, while the NVIDIA B300 provides 4.10 TB/s over a 4096 bit bus. The MI308X has a 1.22 TB/s advantage.

Q: Which GPU supports a larger memory capacity?

A: The MI308X supports 192 GB of HBM3 memory. The B300 supports 144 GB of HBM3e memory. The MI308X holds 48 GB more.

Q: How do the FP16 throughput figures compare?

A: The MI308X lists 81.72 TFLOPS at a 1:1 ratio. The B300 lists 1,231.8 TFLOPS at a 16:1 ratio. The B300 figure is 15.1x higher, but the ratio difference means the comparison depends on the workload's precision path.

Q: What are the thermal design power ratings?

A: The MI308X has a TDP of 750 W with a suggested PSU of 1150 W. The B300 has a TDP of 1400 W with a suggested PSU of 1800 W.

Q: What process node do both GPUs use?

A: Both the MI308X and the B300 are manufactured on a 5 nm process at TSMC. The MI308X uses the Aqua Vanjaram chip with CDNA 3.0 architecture, while the B300 uses the GB110 chip with Blackwell Ultra architecture.

Q: Which GPU has a higher texture rate?

A: The MI308X records 2,553.6 GTexel/s, which is 112.3% higher than the B300's 1,202.9 GTexel/s. The MI308X also has 1,216 TMUs versus 592 on the B300.

Q: When were these GPUs released?

A: The MI308X was released on December 5, 2023. The B300 was released on September 10, 2025. The B300 is listed as Active in production status, while no production status is recorded for the MI308X.

# Architecture Differences

The two GPUs come from different architectural families. The AMD Instinct MI308X uses the CDNA 3.0 architecture with the Aqua Vanjaram chip. The NVIDIA B300 uses the Blackwell Ultra architecture with the GB110 chip. Both are fabricated by TSMC on a 5 nm process.

The MI308X has 153,000 million transistors on a 1017 mm² die, giving a transistor density of 150.4M per mm². The B300 has 104,000 million transistors, but no die size or density figure is recorded. The MI308X therefore has 49,000 million more transistors on a known die area.

Memory architecture differs significantly. The MI308X uses HBM3 with a 8192 bit bus. The B300 uses HBM3e with a 4096 bit bus. The MI308X has double the bus width, while the B300 uses a newer memory type with a higher effective clock of 8 Gbps versus 5.2 Gbps.

The shading unit counts are close: 19,456 on the MI308X versus 18,944 on the B300. The TMU counts diverge sharply: 1,216 versus 592. The ROP counts are 0 for the MI308X and 24 for the B300. The MI308X lists no tensor cores, while the B300 has 592 tensor cores. The MI308X has no pixel rate recorded, while the B300 has 48.77 GPixel/s.

The B300 supports FP16 at a 16:1 ratio, indicating a dedicated tensor path, while the MI308X lists FP16 at 1:1, matching its FP32 rate. The MI308X has no API support recorded for DirectX, OpenGL, or Vulkan. The B300 has null values for those fields as well.

Both GPUs use a PCIe 5.0 x16 bus interface and have no display outputs.

# Specification Differences

The processors differ on clock speeds. The B300 has a base clock of 1665 MHz, which is 665 MHz higher than the MI308X's 1000 MHz. The MI308X has a boost clock of 2100 MHz, which is 68 MHz higher than the B300's 2032 MHz.

Memory clocks differ. The B300 memory runs at 2000 MHz with 8 Gbps effective. The MI308X memory runs at 1300 MHz with 5.2 Gbps effective.

The MI308X has 192 GB of HBM3 memory, while the B300 has 144 GB of HBM3e memory. The bus width is 8192 bit on the MI308X and 4096 bit on the B300. Bandwidth is 5.32 TB/s versus 4.10 TB/s.

FP32 compute is 81.72 TFLOPS on the MI308X and 76.99 TFLOPS on the B300. FP16 is 81.72 TFLOPS at 1:1 on the MI308X and 1,231.8 TFLOPS at 16:1 on the B300.

The MI308X has a TDP of 750 W and a suggested PSU of 1150 W. The B300 has a TDP of 1400 W and a suggested PSU of 1800 W. The MI308X is an OAM Module, while the B300 is an SXM Module. Neither has recorded power connector requirements.

The MI308X has a transistor count of 153,000 million, a die size of 1017 mm², and a transistor density of 150.4M per mm². The B300 has 104,000 million transistors, with no die size or density recorded.

The MI308X has 19,456 shading units, 1,216 TMUs, and 0 ROPs. The B300 has 18,944 shading units, 592 TMUs, and 24 ROPs. The MI308X lists no tensor cores. The B300 lists 592 tensor cores.

The MI308X was released on December 5, 2023. The B300 was released on September 10, 2025. The MI308X belongs to the Instinct (MIx) generation, while the B300 belongs to the Server Blackwell (Bxx) generation. The B300 is listed as Active in production, with its predecessor noted as Server Hopper and its successor as Server Rubin. The MI308X lists its predecessor as Radeon Instinct, with no successor recorded. Neither part has a launch MSRP in the database.