NVIDIA B200 SXM6 vs NVIDIA Rubin GPU Comparison

Where Each One Wins

The recorded data shows a clean split between the two accelerators based on workload type. The NVIDIA B200 SXM6 holds an advantage in raw FP32 throughput per watt, while the NVIDIA Rubin GPU dominates in FP16 compute, memory capacity, and memory bandwidth.

For FP32 workloads, the B200 SXM6 delivers 69.34 TFLOPS, while the Rubin GPU reaches 130.0 TFLOPS. That places Rubin roughly 87% ahead in single-precision math. However, the B200 SXM6 does this within a 1000 W power envelope, whereas the Rubin GPU consumes 2300 W. The efficiency ratio favors the older part: B200 SXM6 produces 69.34 TFLOPS per 1000 W, while Rubin delivers 130.0 TFLOPS per 2300 W, which is a lower per-watt figure.

For FP16 workloads, the separation widens dramatically. The B200 SXM6 runs FP16 at a 1:1 ratio with FP32, meaning it also delivers 69.34 TFLOPS in half-precision. The Rubin GPU runs FP16 at a 2:1 ratio, doubling its FP32 output to reach 260.0 TFLOPS. This means Rubin is roughly 3.75 times faster than B200 SXM6 in FP16 compute. That ratio strongly indicates Rubin is designed for mixed-precision training and inference, where half-precision math dominates.

Memory capacity is another clear differentiator. The B200 SXM6 carries 180 GB of HBM3e, while the Rubin GPU carries 288 GB of HBM4. The Rubin GPU offers 60% more memory, which directly affects the size of models that can reside on a single accelerator without spilling to host memory.

Memory bandwidth tells a similar story. The B200 SXM6 reaches 8.19 TB/s across an 8192-bit bus. The Rubin GPU reaches 22.1 TB/s across a 16384-bit bus. That is a 170% bandwidth advantage for Rubin, a decisive margin for memory-bound workloads such as large transformer inference and graph analytics.

In summary, the B200 SXM6 wins on power efficiency for FP32 tasks, while the Rubin GPU wins decisively on FP16 throughput, memory size, and memory bandwidth. The data does not show any benchmark where the B200 SXM6 outperforms the Rubin GPU on absolute compute or memory metrics.

Architecture Differences

The two accelerators come from different process nodes and foundries. The B200 SXM6 uses a 5 nm process at TSMC, with a die size of 1628 mm² and 208,000 million transistors. The Rubin GPU uses a 3 nm process at TSMC, with a smaller die of 1456 mm² but a far higher transistor count of 336,000 million. The transistor density figures reveal the scaling: B200 SXM6 packs 127.8 million transistors per mm², while Rubin packs 230.8 million per mm². That is an 80% density increase, consistent with the move from 5 nm to 3 nm.

The chip names differ as well. B200 SXM6 uses the GB100 chip under the Blackwell architecture, part of the Server Blackwell (Bxx) generation. Rubin uses the GR100 chip under the Rubin architecture, part of the Server Rubin (Rxx) generation. The Rubin GPU is the successor to the Blackwell server line, and the B200 SXM6 is the predecessor to the Rubin server line.

Memory technology also differs. The B200 SXM6 uses HBM3e with 8 Gbps effective speed, while the Rubin GPU uses HBM4 with 10.8 Gbps effective speed. The bus width doubles from 8192 bit to 16384 bit, which is the primary driver behind the bandwidth jump from 8.19 TB/s to 22.1 TB/s.

Compute resources scale up on Rubin. Shading units increase from 18944 to 28672, TMUs from 592 to 896, and tensor cores from 592 to 896. Both parts keep the same ROP count at 24. The texture rate rises from 1,083.4 GTexel/s to 2,031.2 GTexel/s, while pixel rate rises from 43.92 GPixel/s to 54.41 GPixel/s.

The clock behavior differs notably. The B200 SXM6 runs a base clock of 120 MHz and a boost of 1830 MHz. The Rubin GPU runs a base of 700 MHz and a boost of 2267 MHz. The Rubin GPU has a far higher base clock, which suggests a more stable operating point under load, and a 24% higher boost clock.

Power consumption scales with capability. The B200 SXM6 has a TDP of 1000 W and a suggested PSU of 1400 W. The Rubin GPU has a TDP of 2300 W and a suggested PSU of 2700 W. Both are SXM modules with no display outputs, and both use PCIe 6.0 x16 as the bus interface.

The FP16 ratio change is a key architectural evolution. The B200 SXM6 runs FP16 at 1:1 with FP32, indicating a traditional datacenter compute balance. The Rubin GPU runs FP16 at 2:1, which aligns with the modern trend toward tensor-heavy, low-precision workloads.

FAQ

Q: Which accelerator has more memory?

A: The NVIDIA Rubin GPU has 288 GB of HBM4, while the NVIDIA B200 SXM6 has 180 GB of HBM3e. The Rubin GPU offers 60% more memory capacity.

Q: What is the difference in FP16 compute throughput?

A: The B200 SXM6 delivers 69.34 TFLOPS in FP16 at a 1:1 ratio. The Rubin GPU delivers 260.0 TFLOPS in FP16 at a 2:1 ratio, which is 3.75 times higher.

Q: Which part has a higher boost clock?

A: The Rubin GPU boosts to 2267 MHz, while the B200 SXM6 boosts to 1830 MHz. The Rubin GPU also has a much higher base clock at 700 MHz versus 120 MHz.

Q: How does the process node differ?

A: The B200 SXM6 is built on a 5 nm process at TSMC, while the Rubin GPU is built on a 3 nm process at TSMC. Transistor density rises from 127.8 million per mm² to 230.8 million per mm².

Q: What is the memory bandwidth comparison?

A: The B200 SXM6 reaches 8.19 TB/s across an 8192-bit bus. The Rubin GPU reaches 22.1 TB/s across a 16384-bit bus, a 170% bandwidth advantage.

Q: Which accelerator has more tensor cores?

A: The Rubin GPU has 896 tensor cores, while the B200 SXM6 has 592 tensor cores. The Rubin GPU also has 896 TMUs versus 592 TMUs on the B200 SXM6.

Specification Differences

The two accelerators differ across nearly every major specification field.

| Specification | NVIDIA B200 SXM6 | NVIDIA Rubin GPU |

|---|---|---|

| Chip | GB100 | GR100 |

| Architecture | Blackwell | Rubin |

| Generation | Server Blackwell (Bxx) | Server Rubin (Rxx) |

| Process node | 5 nm | 3 nm |

| Transistors | 208,000 million | 336,000 million |

| Die size | 1628 mm² | 1456 mm² |

| Transistor density | 127.8M / mm² | 230.8M / mm² |

| Base clock | 120 MHz | 700 MHz |

| Boost clock | 1830 MHz | 2267 MHz |

| Memory clock | 2000 MHz, 8 Gbps effective | 2695 MHz, 10.8 Gbps effective |

| Memory size | 180 GB | 288 GB |

| Memory type | HBM3e | HBM4 |

| Memory bus width | 8192 bit | 16384 bit |

| Memory bandwidth | 8.19 TB/s | 22.1 TB/s |

| Shading units | 18944 | 28672 |

| TMUs | 592 | 896 |

| ROPs | 24 | 24 |

| Tensor cores | 592 | 896 |

| Pixel rate | 43.92 GPixel/s | 54.41 GPixel/s |

| Texture rate | 1,083.4 GTexel/s | 2,031.2 GTexel/s |

| FP32 performance | 69.34 TFLOPS | 130.0 TFLOPS |

| FP16 performance | 69.34 TFLOPS (1:1) | 260.0 TFLOPS (2:1) |

| TDP | 1000 W | 2300 W |

| Suggested PSU | 1400 W | 2700 W |

| Release date | 2024-10-31 | 2025-12-31 |

| Predecessor | Server Hopper | Server Blackwell |

| Successor | Server Rubin | None listed |

The B200 SXM6 has a launch MSRP of 34,999 USD. No launch MSRP is recorded for the Rubin GPU.

Head-to-Head Benchmarks

The database contains no direct head-to-head benchmark entries for these two accelerators, and neither part has individual benchmark scores recorded. Both sit at the 50th percentile among all GPUs in the database, with an average benchmark score of 0.

Without measured benchmark runs, the comparison must rely on the recorded hardware specifications. The largest performance gap appears in FP16 compute. The Rubin GPU produces 260.0 TFLOPS versus 69.34 TFLOPS for the B200 SXM6, a difference of 190.66 TFLOPS. In relative terms, Rubin delivers 3.75 times the half-precision throughput.

The second largest gap is memory bandwidth. Rubin reaches 22.1 TB/s, while the B200 SXM6 reaches 8.19 TB/s. The absolute difference is 13.91 TB/s, and the relative difference is 2.7 times.

FP32 compute also swings heavily toward Rubin. The Rubin GPU delivers 130.0 TFLOPS versus 69.34 TFLOPS, an absolute difference of 60.66 TFLOPS. In relative terms, Rubin is 1.87 times faster.

Texture rate shows a similar pattern. Rubin reaches 2,031.2 GTexel/s, while the B200 SXM6 reaches 1,083.4 GTexel/s. That is 1.87 times higher, matching the FP32 ratio because texture rate scales with the number of TMUs and clock speed.

Pixel rate is the narrowest difference. Rubin delivers 54.41 GPixel/s versus 43.92 GPixel/s for the B200 SXM6. That is 1.24 times higher, a modest gain given that both parts have 24 ROPs.

Memory capacity favors Rubin by 108 GB, moving from 180 GB to 288 GB. This is a 1.6 times increase.

The transistor count difference is also large. Rubin has 336,000 million transistors versus 208,000 million for the B200 SXM6, a 128,000 million difference. Despite a smaller die, Rubin packs far more transistors due to the denser 3 nm process.

Clock speeds favor Rubin on both ends. The base clock rises from 120 MHz to 700 MHz, a 5.8 times increase. The boost clock rises from 1830 MHz to 2267 MHz, a 1.24 times increase. The base clock jump is particularly notable because it indicates the Rubin GPU can sustain a much higher floor performance.

Power consumption scales up as well. The TDP moves from 1000 W to 2300 W, a 2.3 times increase. The suggested PSU moves from 1400 W to 2700 W, a 1.93 times increase.

The only specification where the B200 SXM6 holds an advantage is die size, at 1628 mm² versus 1456 mm². This is not a performance metric, but it does indicate the B200 SXM6 uses more silicon area to achieve its lower transistor count, a reflection of the older process node.

The Verdict

The data points to a clear generational shift. The NVIDIA Rubin GPU surpasses the NVIDIA B200 SXM6 in every compute and memory metric recorded in the database. The FP16 figure is the most striking: Rubin delivers 260.0 TFLOPS versus 69.34 TFLOPS, a 3.75 times advantage. This alone positions Rubin for workloads that rely on half-precision tensor math, such as large-scale model training and inference.

Memory capacity and bandwidth follow the same direction. Rubin offers 288 GB of HBM4 at 22.1 TB/s, while the B200 SXM6 offers 180 GB of HBM3e at 8.19 TB/s. The bandwidth gap of 2.7 times means Rubin can feed its larger compute array far more effectively. For memory-bound workloads, this is the decisive specification.

The B200 SXM6 retains one practical advantage: power efficiency in FP32. It delivers 69.34 TFLOPS within a 1000 W TDP, while Rubin delivers 130.0 TFLOPS within a 2300 W TDP. The B200 SXM6 produces 69.34 TFLOPS per 1000 W, which is 0.069 TFLOPS per watt. Rubin produces 130.0 TFLOPS per 2300 W, which is 0.057 TFLOPS per watt. The B200 SXM6 is roughly 21% more efficient in FP32 per watt. For deployments constrained by power delivery or cooling, the B200 SXM6 remains a viable option.

However, the FP16 efficiency tells the opposite story. Rubin produces 260.0 TFLOPS per 2300 W, which is 0.113 TFLOPS per watt. The B200 SXM6 produces 69.34 TFLOPS per 1000 W, which is 0.069 TFLOPS per watt. Rubin is 64% more efficient in FP16 per watt. Since modern AI workloads predominantly use FP16 or lower precision, the efficiency balance favors Rubin in practice.

The Rubin GPU also has the advantage of a higher boost clock, a higher base clock, more shading units, more TMUs, more tensor cores, and a denser process node. The only meaningful counterpoints for the B200 SXM6 are its lower power draw, its lower suggested PSU, and its earlier release date.

For users who run FP32-heavy workloads with strict power limits, the B200 SXM6 is the more sensible choice. For anyone running FP16 training or inference, or requiring large memory capacity and high bandwidth, the Rubin GPU is the clear selection based on the recorded specifications. The database shows no benchmark where the B200 SXM6 wins on absolute performance. The Rubin GPU is the successor in every measurable way.