NVIDIA H800 SXM5 vs NVIDIA Rubin GPU Comparison

# Where Each One Wins

The recorded data for the NVIDIA H800 SXM5 and the NVIDIA Rubin GPU shows no head-to-head benchmark comparisons, no individual benchmark scores, and no win counts for either product. This makes a direct per-application victory split impossible from the database. Instead, the measurable distinctions come from the hardware specifications, and those point to clearly separate roles.

The H800 SXM5 is built for memory bandwidth and FP16 throughput relative to its power envelope. It delivers 3.36 TB/s of bandwidth from 80 GB of HBM3 across a 5120-bit bus. Its FP16 rate is 237.2 TFLOPS (4:1), which is the highest compute figure on its side. The Rubin GPU counters with 22.1 TB/s of bandwidth from 288 GB of HBM4 across a 16384-bit bus, and its FP16 rate is 260.0 TFLOPS (2:1). The Rubin GPU also leads in FP32, 130.0 TFLOPS versus 59.30 TFLOPS, and in texture rate, 2,031.2 GTexel/s versus 926.6 GTexel/s.

Where the H800 SXM5 wins is in operational practicality. Its 700 W TDP and 1100 W suggested PSU are far lower than the Rubin GPU's 2300 W TDP and 2700 W suggested PSU. The H800 SXM5 uses a PCIe 5.0 x16 interface, while the Rubin GPU uses PCIe 6.0 x16. Both are SXM modules with no display outputs. The H800 SXM5 is already in production with a release date of March 2023, whereas the Rubin GPU has a release date of December 2025. For systems that need a Hopper-generation accelerator available today, the H800 SXM5 is the only choice between these two.

The Rubin GPU wins on raw capacity and speed. It has 336,000 million transistors on a 1456 mm² die at 3 nm, versus 80,000 million transistors on an 814 mm² die at 5 nm. Shading units are 28,672 versus 16,896, TMUs are 896 versus 528, tensor cores are 896 versus 528. Pixel rate is 54.41 GPixel/s versus 42.12 GPixel/s. Memory size is 288 GB versus 80 GB, and bandwidth is more than six times higher. Every major compute resource favors the Rubin GPU.

# Architecture Differences

The two GPUs come from different architectural generations. The H800 SXM5 uses the GH100 chip with the Hopper architecture, classified in the Server Hopper (Hxx) generation. The Rubin GPU uses the GR100 chip with the Rubin architecture, classified in the Server Rubin (Rxx) generation. Both are manufactured by TSMC, but the process nodes differ: the H800 SXM5 is on 5 nm, the Rubin GPU on 3 nm. Transistor density reflects this, 98.3M per mm² for the H800 SXM5, 230.8M per mm² for the Rubin GPU.

The memory subsystems are entirely different. The H800 SXM5 uses HBM3 with 80 GB, a 5120-bit bus, and 3.36 TB/s bandwidth. Memory clock is 1313 MHz with 5.3 Gbps effective. The Rubin GPU uses HBM4 with 288 GB, a 16384-bit bus, and 22.1 TB/s bandwidth. Memory clock is 2695 MHz with 10.8 Gbps effective. The bus width triples, and the bandwidth more than sextuples.

Compute resources scale up substantially. The H800 SXM5 has 16,896 shading units, 528 TMUs, 24 ROPs, and 528 tensor cores. The Rubin GPU has 28,672 shading units, 896 TMUs, 24 ROPs, and 896 tensor cores. The ROP count is identical at 24, which is a notable shared trait. The FP16 ratio differs: the H800 SXM5 lists 237.2 TFLOPS at a 4:1 ratio, the Rubin GPU lists 260.0 TFLOPS at a 2:1 ratio. The FP32 figures are 59.30 TFLOPS and 130.0 TFLOPS respectively.

Clock behavior is also distinct. The H800 SXM5 has a base clock of 1095 MHz and a boost clock of 1755 MHz. The Rubin GPU has a base clock of 700 MHz and a boost clock of 2267 MHz. The Rubin GPU starts lower but boosts much higher, which likely reflects a different power management design given its 2300 W TDP. The H800 SXM5 has a 700 W TDP.

Interface and power delivery differ. The H800 SXM5 uses an 8-pin EPS power connector and a PCIe 5.0 x16 bus. The Rubin GPU has no listed power connector and uses a PCIe 6.0 x16 bus. Both are SXM modules with no display outputs. The H800 SXM5 lists no API support details, while the Rubin GPU explicitly lists DirectX, OpenGL, and Vulkan as N/A.

# Head-to-Head Benchmarks

The database contains no head-to-head benchmark entries for these two GPUs. There are no recorded benchmark scores, no win counts, and no nearest rivals for either product. This means a numerical comparison of performance in specific workloads cannot be drawn from the data. What can be compared are the specification-derived capabilities, which are substantial.

The largest single gap is memory bandwidth. The Rubin GPU's 22.1 TB/s is approximately 6.58 times the H800 SXM5's 3.36 TB/s. That ratio comes directly from the listed figures. Memory capacity follows a similar pattern: 288 GB versus 80 GB, which is 3.6 times more. The bus width jumps from 5120 bit to 16384 bit, exactly three times wider.

In compute, the FP32 rate of the Rubin GPU, 130.0 TFLOPS, is 2.19 times the H800 SXM5's 59.30 TFLOPS. The FP16 rates are closer: 260.0 TFLOPS versus 237.2 TFLOPS, a 1.10 times advantage. Texture rate is 2,031.2 GTexel/s versus 926.6 GTexel/s, a 2.19 times gap. Pixel rate is 54.41 GPixel/s versus 42.12 GPixel/s, a 1.29 times gap.

The transistor count difference is the most extreme. The Rubin GPU packs 336,000 million transistors, which is 4.2 times the H800 SXM5's 80,000 million. Die size grows from 814 mm² to 1456 mm², a 1.79 times increase, but the density improvement from 5 nm to 3 nm allows the transistor count to grow far faster than the die area.

Clock speeds cut the other way. The H800 SXM5 has a higher base clock, 1095 MHz versus 700 MHz, but the Rubin GPU's boost clock is higher, 2267 MHz versus 1755 MHz. The H800 SXM5's boost is 1.60 times its base, while the Rubin GPU's boost is 3.24 times its base. This suggests the Rubin GPU relies heavily on boost behavior to reach its peak rates.

Power figures are stark. The Rubin GPU's 2300 W TDP is 3.29 times the H800 SXM5's 700 W. The suggested PSU scales similarly: 2700 W versus 1100 W, a 2.45 times increase. The H800 SXM5 delivers 3.36 TB/s at 700 W, which is 4.8 GB/s per watt. The Rubin GPU delivers 22.1 TB/s at 2300 W, which is 9.61 GB/s per watt. The Rubin GPU is more bandwidth-efficient per watt despite the higher absolute power draw.

# The Verdict

The data supports a clear split. The H800 SXM5 is the choice for deployments that require a Hopper-generation accelerator with moderate power requirements and a release date that has already passed. It offers 80 GB of HBM3, 3.36 TB/s of bandwidth, and 59.30 TFLOPS of FP32 at 700 W. Its FP16 rate of 237.2 TFLOPS is close to the Rubin GPU's 260.0 TFLOPS, making it competitive for mixed-precision workloads where power and cooling are constrained.

The Rubin GPU is the choice for maximum capacity and throughput. It has 288 GB of HBM4, 22.1 TB/s of bandwidth, 130.0 TFLOPS of FP32, and 260.0 TFLOPS of FP16. It uses a PCIe 6.0 x16 interface and has a release date of December 2025. The 2300 W TDP and 2700 W suggested PSU indicate it is designed for high-end server installations with robust power infrastructure.

Neither product has benchmark scores or nearest rival comparisons in the database. The percentile ranking for both is 50, and the average benchmark score for both is 0. This means the verdict rests entirely on specification analysis. The H800 SXM5's 3.36 TB/s bandwidth at 700 W gives it a bandwidth-per-watt of 4.8 GB/s per watt, while the Rubin GPU's 22.1 TB/s at 2300 W gives 9.61 GB/s per watt. The Rubin GPU is more efficient in that metric.

The H800 SXM5 fits systems that already support PCIe 5.0 and need a proven Hopper part. The Rubin GPU fits new builds that can accommodate PCIe 6.0 and high power delivery. The ROP count is identical at 24, so pixel output differences are modest, 54.41 GPixel/s versus 42.12 GPixel/s. For workloads that are memory-bound, the Rubin GPU's 22.1 TB/s is the decisive advantage. For workloads that are power-bound, the H800 SXM5's 700 W envelope is the decisive advantage.

# FAQ

Q: Which GPU has more memory bandwidth?

A: The NVIDIA Rubin GPU has 22.1 TB/s from HBM4, while the NVIDIA H800 SXM5 has 3.36 TB/s from HBM3. The Rubin GPU's bandwidth is over six times higher.

Q: What is the difference in FP32 compute performance?

A: The Rubin GPU delivers 130.0 TFLOPS, while the H800 SXM5 delivers 59.30 TFLOPS. The Rubin GPU is 2.19 times faster in FP32.

Q: Do both GPUs have the same number of ROPs?

A: Yes, both have 24 ROPs. The pixel rates differ because of clock speeds: 54.41 GPixel/s for the Rubin GPU versus 42.12 GPixel/s for the H800 SXM5.

Q: What are the power requirements for each?

A: The H800 SXM5 has a 700 W TDP and a suggested PSU of 1100 W. The Rubin GPU has a 2300 W TDP and a suggested PSU of 2700 W.

Q: Which GPU uses a newer memory type?

A: The Rubin GPU uses HBM4 with a 16384-bit bus and 2695 MHz memory clock. The H800 SXM5 uses HBM3 with a 5120-bit bus and 1313 MHz memory clock.

Q: Are there any benchmark scores available for these two GPUs?

A: No. The database lists no benchmark scores, no head-to-head results, and no nearest rivals for either product. The average benchmark score is 0 for both.

# Specification Differences

The following fields differ between the NVIDIA H800 SXM5 and the NVIDIA Rubin GPU:

• Chip: GH100 versus GR100
• Architecture: Hopper versus Rubin
• Generation: Server Hopper (Hxx) versus Server Rubin (Rxx)
• Process node: 5 nm versus 3 nm
• Transistors: 80,000 million versus 336,000 million
• Die size: 814 mm² versus 1456 mm²
• Transistor density: 98.3M / mm² versus 230.8M / mm²
• Base clock: 1095 MHz versus 700 MHz
• Boost clock: 1755 MHz versus 2267 MHz
• Memory clock: 1313 MHz, 5.3 Gbps effective versus 2695 MHz, 10.8 Gbps effective
• Memory size: 80 GB versus 288 GB
• Memory type: HBM3 versus HBM4
• Bus width: 5120 bit versus 16384 bit
• Bandwidth: 3.36 TB/s versus 22.1 TB/s
• Shading units: 16,896 versus 28,672
• TMUs: 528 versus 896
• Tensor cores: 528 versus 896
• Pixel rate: 42.12 GPixel/s versus 54.41 GPixel/s
• Texture rate: 926.6 GTexel/s versus 2,031.2 GTexel/s
• FP32: 59.30 TFLOPS versus 130.0 TFLOPS
• FP16: 237.2 TFLOPS (4:1) versus 260.0 TFLOPS (2:1)
• TDP: 700 W versus 2300 W
• Power connectors: 8-pin EPS versus not listed
• Suggested PSU: 1100 W versus 2700 W
• Bus interface: PCIe 5.0 x16 versus PCIe 6.0 x16
• API support: no listings versus DirectX, OpenGL, Vulkan all N/A
• Release date: 2023-03-20 versus 2025-12-31
• Predecessor: Server Ada versus Server Blackwell
• Successor: Server Blackwell versus not listed

Fields that are identical: manufacturer (NVIDIA), foundry (TSMC), ROPs (24), slot width (SXM Module), display outputs (no outputs), production status (Active), launch MSRP (not listed).