NVIDIA H800 PCIe 80 GB vs NVIDIA Rubin GPU Comparison

Head-to-Head Benchmarks

The database contains no recorded benchmark scores for either GPU. Both the NVIDIA H800 PCIe 80 GB and the NVIDIA Rubin GPU have empty benchmark arrays, zero average benchmark scores, and zero head-to-head benchmark entries. The wins tally stands at 0 for each product. This means the comparative performance picture must be derived entirely from architectural specifications and theoretical throughput figures rather than measured application results.

The raw compute figures, however, tell a clear story of generational scaling. The Rubin GPU delivers 130.0 TFLOPS of FP32 throughput, which is 2.54 times the H800's 51.22 TFLOPS. In FP16 compute, the Rubin GPU reaches 260.0 TFLOPS (2:1 ratio), compared to the H800's 204.9 TFLOPS (4:1 ratio). The Rubin GPU's FP16 advantage is 1.27 times, but the ratio difference matters: the H800's FP16 figure is achieved through a 4:1 tensor core operation, while the Rubin GPU's 2:1 ratio implies a different architectural trade-off in how the tensor cores are utilized.

Texture and pixel throughput show similarly lopsided comparisons. The Rubin GPU's texture rate of 2,031.2 GTexel/s is 2.54 times the H800's 800.3 GTexel/s, matching the FP32 scaling exactly since both products have the same ratio of texture mapping units to shading units. Pixel rate favors the Rubin GPU by 1.29 times (54.41 GPixel/s versus 42.12 GPixel/s), a smaller gap because both GPUs are limited to 24 ROPs, a rare point of parity between the two designs.

Memory bandwidth delivers the most dramatic difference. The Rubin GPU's 22.1 TB/s bandwidth is 10.83 times the H800's 2.04 TB/s. This is not merely a linear scaling; it reflects a fundamental redesign of the memory subsystem, discussed in the architecture section. The bus width increase from 5120 bit to 16384 bit (3.2 times) combines with a memory clock jump from 1593 MHz (3.2 Gbps effective) to 2695 MHz (10.8 Gbps effective, 3.375 times) to produce the tenfold bandwidth leap.

Clock behavior presents an interesting inversion. The H800 has a higher base clock (1095 MHz versus 700 MHz) but a lower boost clock (1755 MHz versus 2267 MHz). The Rubin GPU's boost clock is 1.29 times higher, yet its base clock is 0.64 times lower. This suggests the Rubin GPU is designed for bursty, high-power workloads where sustained boost is the norm, while the H800's more conservative clock envelope reflects its 350 W power target versus the Rubin GPU's 2300 W.

Architecture Differences

The two GPUs span two distinct architectural generations. The H800 PCIe 80 GB uses the GH100 chip, built on the Hopper architecture, part of the Server Hopper (Hxx) generation. The Rubin GPU uses the GR100 chip, built on the Rubin architecture, part of the Server Rubin (Rxx) generation. Their production status is Active for both, but the release dates differ: the H800 launched on March 20, 2023, while the Rubin GPU's release date is December 31, 2025. The H800's successor is listed as Server Blackwell, and the Rubin GPU's predecessor is Server Blackwell, placing the two products on opposite sides of an intervening generation.

The manufacturing process advances from 5 nm to 3 nm, both at TSMC. Transistor counts scale massively: the H800 packs 80,000 million transistors on an 814 mm² die, while the Rubin GPU contains 336,000 million transistors on a 1456 mm² die. This is a 4.2 times increase in transistor count and a 1.79 times increase in die area. Transistor density improves from 98.3M per mm² to 230.8M per mm², a 2.35 times density gain from the process shrink alone.

Shader resources scale substantially. The Rubin GPU has 28,672 shading units versus 14,592 on the H800 (1.97 times), 896 texture mapping units versus 456 (1.96 times), and 896 tensor cores versus 456 (1.96 times). Both GPUs have 24 ROPs, an unusual parity given the scale of other resource increases. Neither GPU lists ray tracing cores in the database.

Memory architecture is the most striking divergence. The H800 uses 80 GB of HBM2e on a 5120 bit bus, yielding 2.04 TB/s. The Rubin GPU uses 288 GB of HBM4 on a 16384 bit bus, yielding 22.1 TB/s. Memory capacity grows 3.6 times, bus width grows 3.2 times, and bandwidth grows 10.83 times. The memory type change from HBM2e to HBM4 accounts for the effective clock speed increase from 3.2 Gbps to 10.8 Gbps.

Physical and interface specifications differ profoundly. The H800 is a dual-slot PCIe card, 268 mm long and 111 mm tall, using a 1x 16-pin power connector, with a 750 W suggested PSU and PCIe 5.0 x16 interface. The Rubin GPU is an SXM module with no listed dimensions, no power connector listed, a 2700 W suggested PSU, and PCIe 6.0 x16 interface. The Rubin GPU's API support is explicitly listed as N/A for DirectX, OpenGL, and Vulkan, while the H800 has null values in those fields; both are server parts with no display outputs.

FAQ

Q: Which GPU has higher FP32 compute throughput?

A: The Rubin GPU delivers 130.0 TFLOPS of FP32, which is 2.54 times the H800's 51.22 TFLOPS.

Q: How do the memory bandwidth figures compare?

A: The Rubin GPU's 22.1 TB/s is 10.83 times the H800's 2.04 TB/s. The Rubin GPU uses 288 GB of HBM4 on a 16384 bit bus, while the H800 uses 80 GB of HBM2e on a 5120 bit bus.

Q: What are the power requirements for each GPU?

A: The H800 has a TDP of 350 W and a suggested PSU of 750 W. The Rubin GPU has a TDP of 2300 W and a suggested PSU of 2700 W.

Q: How do the transistor counts differ?

A: The Rubin GPU contains 336,000 million transistors on a 1456 mm² die, while the H800 contains 80,000 million transistors on an 814 mm² die. The Rubin GPU has 4.2 times more transistors on 1.79 times the die area.

Q: Which GPU has a higher boost clock?

A: The Rubin GPU boosts to 2267 MHz, which is 1.29 times the H800's 1755 MHz boost clock. However, the H800 has a higher base clock at 1095 MHz versus the Rubin GPU's 700 MHz.

Q: Are these GPUs identical in ROP count?

A: Yes, both the H800 and the Rubin GPU have 24 ROPs, despite the Rubin GPU having roughly twice the shading units, texture mapping units, and tensor cores.

Specification Differences

| Specification | NVIDIA H800 PCIe 80 GB | NVIDIA Rubin GPU |

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

| Architecture | Hopper | Rubin |

| Generation | Server Hopper (Hxx) | Server Rubin (Rxx) |

| Chip | GH100 | GR100 |

| Process Node | 5 nm | 3 nm |

| Transistors | 80,000 million | 336,000 million |

| Die Size | 814 mm² | 1456 mm² |

| Transistor Density | 98.3M / mm² | 230.8M / mm² |

| Base Clock | 1095 MHz | 700 MHz |

| Boost Clock | 1755 MHz | 2267 MHz |

| Memory Clock | 1593 MHz, 3.2 Gbps effective | 2695 MHz, 10.8 Gbps effective |

| Memory Size | 80 GB | 288 GB |

| Memory Type | HBM2e | HBM4 |

| Memory Bus Width | 5120 bit | 16384 bit |

| Memory Bandwidth | 2.04 TB/s | 22.1 TB/s |

| Shading Units | 14592 | 28672 |

| TMUs | 456 | 896 |

| Tensor Cores | 456 | 896 |

| Pixel Rate | 42.12 GPixel/s | 54.41 GPixel/s |

| Texture Rate | 800.3 GTexel/s | 2,031.2 GTexel/s |

| FP32 | 51.22 TFLOPS | 130.0 TFLOPS |

| FP16 | 204.9 TFLOPS (4:1) | 260.0 TFLOPS (2:1) |

| TDP | 350 W | 2300 W |

| Slot Width | Dual-slot | SXM Module |

| Power Connectors | 1x 16-pin | None listed |

| Suggested PSU | 750 W | 2700 W |

| Bus Interface | PCIe 5.0 x16 | PCIe 6.0 x16 |

| Dimensions | 268 mm length, 111 mm height | Not listed |

| Release Date | March 20, 2023 | December 31, 2025 |

| Predecessor | Server Ada | Server Blackwell |

| Successor | Server Blackwell | None listed |

| APIs | Null for DirectX, OpenGL, Vulkan | N/A for DirectX, OpenGL, Vulkan |

The Verdict

The data presents two GPUs with no overlapping performance profiles. The H800 PCIe 80 GB is a 350 W dual-slot PCIe card from the Hopper generation, designed for a 2023-era server environment with PCIe 5.0. The Rubin GPU is a 2300 W SXM module from the Rubin generation, targeting a 2025-era deployment with PCIe 6.0, and requires a 2700 W PSU.

The Rubin GPU wins every compute metric in the database: FP32 by 2.54 times, FP16 by 1.27 times, texture rate by 2.54 times, pixel rate by 1.29 times, and memory bandwidth by 10.83 times. It also holds a 3.6 times memory capacity advantage. The H800's only clock advantage is its base clock, where it runs at 1095 MHz versus 700 MHz, but the Rubin GPU's boost clock is 1.29 times higher.

The architecture gap is fundamental. The Rubin GPU uses a 3 nm process versus 5 nm, packs 4.2 times more transistors, and uses HBM4 versus HBM2e. The die size grows from 814 mm² to 1456 mm², and transistor density improves from 98.3M per mm² to 230.8M per mm².

The choice between these products depends entirely on deployment context. The H800's 350 W TDP and dual-slot PCIe form factor make it compatible with standard server chassis and air-cooled environments. The Rubin GPU's 2300 W TDP and SXM module form factor require specialized infrastructure, likely liquid cooling and proprietary server platforms, based on the power connector absence and the 2700 W PSU recommendation.

Where Each One Wins

The H800 PCIe 80 GB wins in power efficiency scenarios. Its 350 W TDP is 0.15 times the Rubin GPU's 2300 W, and its 750 W suggested PSU is 0.28 times the Rubin GPU's 2700 W. The H800's dual-slot form factor and PCIe 5.0 x16 interface allow deployment in standard PCIe slots, while the Rubin GPU's SXM module form factor implies a proprietary mounting system. The H800's higher base clock (1095 MHz versus 700 MHz) suggests better sustained performance at lower power states.

The H800 also wins on physical footprint for dense installations. Its 268 mm length and 111 mm height are specified in the database, while the Rubin GPU has no listed dimensions, indicating the H800 can be planned into existing rack layouts with known clearance requirements.

The Rubin GPU wins on every raw performance metric. Its 130.0 TFLOPS FP32 and 260.0 TFLOPS FP16 represent 2.54 times and 1.27 times the H800's figures, respectively. The 22.1 TB/s memory bandwidth is 10.83 times higher, which matters for data-intensive workloads that saturate memory. The 288 GB capacity versus 80 GB means 3.6 times more data can reside on-device.

The Rubin GPU's 896 tensor cores versus 456 is a 1.96 times advantage, and its 28,672 shading units versus 14,592 is a 1.97 times advantage. The 2,031.2 GTexel/s texture rate versus 800.3 GTexel/s is a 2.54 times advantage. The Rubin GPU also wins on interface generation, using PCIe 6.0 x16 versus the H800's PCIe 5.0 x16, and on memory technology, using HBM4 versus HBM2e.

The Rubin GPU's release date of December 31, 2025 places it roughly 2.8 years after the H800's March 20, 2023 launch, explaining the architectural leap. The H800's successor is Server Blackwell, while the Rubin GPU's predecessor is Server Blackwell, confirming the Rubin GPU sits one full generation ahead in the product stack. The ROP parity at 24 for both GPUs means pixel fill rate is not a differentiator in the same way compute and memory are, though the Rubin GPU still wins pixel rate by 1.29 times due to its higher boost clock.