AMD Radeon Instinct MI300 vs NVIDIA Rubin GPU Comparison

FAQ

Q: What are the two GPUs compared in this analysis?

A: The AMD Radeon Instinct MI300 and the NVIDIA Rubin GPU. The MI300 is an AMD data center accelerator built on the CDNA 3.0 architecture, while the Rubin GPU is an NVIDIA server processor based on the Rubin architecture.

Q: How do their manufacturing processes differ?

A: The AMD Radeon Instinct MI300 is fabricated on a 5 nm process at TSMC, while the NVIDIA Rubin GPU uses a more advanced 3 nm process, also from TSMC. The smaller node allows the Rubin GPU to pack more transistors into a larger die.

Q: What are the memory configurations of each card?

A: The MI300 features 128 GB of HBM3 memory on an 8192-bit bus, delivering 6.55 TB/s of bandwidth. The Rubin GPU offers 288 GB of HBM4 memory on a 16384-bit bus, achieving 22.1 TB/s of bandwidth.

Q: Which GPU has a higher boost clock?

A: The NVIDIA Rubin GPU has a boost clock of 2267 MHz, which is substantially higher than the AMD MI300's boost clock of 1700 MHz. The MI300 does have a higher base clock at 1000 MHz versus 700 MHz for the Rubin.

Q: What is the average benchmark score for these accelerators?

A: Both the AMD Radeon Instinct MI300 and the NVIDIA Rubin GPU have an average benchmark score of 0 in the database. They both sit at the 50th percentile when compared against all GPUs.

Q: Do either of these cards support display outputs?

A: No. Both the AMD Radeon Instinct MI300 and the NVIDIA Rubin GPU have no display outputs, confirming their dedicated data center and server roles.

Architecture Differences

The AMD Radeon Instinct MI300 and NVIDIA Rubin GPU represent two distinct architectural approaches to high-performance computing, differentiated primarily by process technology, core organization, and memory design.

The MI300 uses the CDNA 3.0 architecture, which is AMD's dedicated compute-focused design. It is built on a 5 nm process at TSMC, with a die size of 1017 mm². The chip, codenamed Aqua Vanjaram, contains 153,000 million transistors, resulting in a transistor density of 150.4 million transistors per mm². The Rubin GPU, in contrast, uses the Rubin architecture on a 3 nm TSMC process, with a larger die size of 1456 mm². It houses 336,000 million transistors, which translates to a density of 230.8 million transistors per mm². The data shows the Rubin GPU achieves a 53% higher transistor density despite the larger physical die.

Core configuration differs substantially between the two. The MI300 has 14,080 shading units, 880 texture mapping units, and zero ROPs. The Rubin GPU has 28,672 shading units, 896 texture mapping units, and 24 ROPs. This means the Rubin has just over twice the shading units and slightly more TMUs, while the MI300 has no ROPs at all. The Rubin also includes 896 tensor cores, a feature that the MI300 does not list.

Memory architecture is another major divider. The MI300 uses 128 GB of HBM3 on an 8192-bit bus. The Rubin GPU uses 288 GB of HBM4 on a 16384-bit bus. The bandwidth gap is large: 6.55 TB/s for the MI300 versus 22.1 TB/s for the Rubin. The Rubin's memory bus is exactly twice as wide, and its memory clock runs at 2695 MHz (10.8 Gbps effective) compared to 1600 MHz (6.4 Gbps effective) for the MI300.

Clock behavior also separates the two. The MI300 has a base clock of 1000 MHz and a boost clock of 1700 MHz. The Rubin has a lower base of 700 MHz but a much higher boost of 2267 MHz. This suggests the Rubin can reach higher peak performance under load, while the MI300 maintains a higher idle or baseline frequency.

Power delivery and form factor differ as well. The MI300 has a TDP of 600 W, uses 2x 8-pin power connectors, and requires a suggested power supply of 1000 W. The Rubin GPU has a TDP of 2300 W, uses an SXM Module slot width, and requires a suggested power supply of 2700 W. The MI300 is a PCIe 5.0 x16 card with physical dimensions of 267 mm in length and 111 mm in height. The Rubin uses PCIe 6.0 x16 and has no listed dimensions.

Head-to-Head Benchmarks

The database records no direct head-to-head benchmark entries between the AMD Radeon Instinct MI300 and the NVIDIA Rubin GPU. Neither card has any listed benchmark scores, and the wins count is zero for both sides. However, the specification data provides a basis for comparing their theoretical compute and throughput capabilities.

In raw floating-point performance, the NVIDIA Rubin GPU leads decisively. The Rubin delivers 130.0 TFLOPS of FP32 compute, while the MI300 delivers 47.87 TFLOPS. This means the Rubin offers 2.7 times the FP32 throughput of the MI300. The gap is even more pronounced in absolute terms: the Rubin exceeds the MI300 by 82.13 TFLOPS in FP32.

The FP16 comparison is more nuanced. The MI300 lists FP16 at 383.0 TFLOPS, but this is measured at an 8:1 ratio, meaning it uses a reduced-precision mode to achieve that figure. The Rubin lists FP16 at 260.0 TFLOPS at a 2:1 ratio. The MI300's FP16 figure is 47% higher than the Rubin's, but the difference in ratio means the comparison is not directly equivalent. The MI300's FP16 advantage comes from a more aggressive precision reduction.

Texture rate favors the Rubin GPU. The Rubin achieves 2,031.2 GTexel/s, while the MI300 achieves 1,496.0 GTexel/s. This is a 35.8% advantage for the Rubin in texture fill rate, consistent with its higher TMU count and boost clock. The pixel rate comparison is one-sided: the MI300 has a pixel rate of 0 MPixel/s because it has no ROPs, while the Rubin produces 54.41 GPixel/s.

Memory bandwidth is the most lopsided specification. The Rubin GPU's 22.1 TB/s is 3.37 times the MI300's 6.55 TB/s. This is driven by the Rubin's larger memory pool, wider bus, faster memory clock, and newer HBM4 standard. For memory-bound workloads, the Rubin would process data at a far higher rate.

The transistor and die data reinforce the Rubin's performance positioning. With 336,000 million transistors versus 153,000 million for the MI300, the Rubin has 2.2 times the transistor count. Its die size of 1456 mm² is 43% larger than the MI300's 1017 mm². The density difference also matters: 230.8M transistors per mm² for the Rubin versus 150.4M for the MI300, indicating a more efficient use of silicon area.

The power envelope is similarly lopsided. The Rubin GPU draws 2300 W, which is 3.83 times the MI300's 600 W TDP. The suggested power supply values follow the same pattern: 2700 W for the Rubin versus 1000 W for the MI300. This means the Rubin's performance comes at a very high power cost, while the MI300 offers a more power-conscious alternative.

The release timeline shows the MI300 launched on January 3, 2023, while the Rubin GPU is dated December 31, 2025. The Rubin is listed as an active production part, while the MI300 has no production status listed. The Rubin's predecessor is Server Blackwell, and the MI300's predecessor is FirePro Data Center.

The Verdict

The recorded data indicates a clear performance hierarchy, but the choice between these two accelerators depends on workload priorities and power constraints.

The NVIDIA Rubin GPU is the higher-performance part by nearly every compute metric. Its FP32 throughput of 130.0 TFLOPS is 2.7 times the MI300's 47.87 TFLOPS. Its memory bandwidth of 22.1 TB/s is over three times the MI300's 6.55 TB/s. Its texture rate of 2,031.2 GTexel/s beats the MI300's 1,496.0 GTexel/s, and it offers pixel output where the MI300 has none. The Rubin also carries more shading units, more transistors, and a newer memory standard. For maximum raw compute and memory throughput, the Rubin is the data-supported choice.

The AMD Radeon Instinct MI300 has its own advantages. Its FP16 figure of 383.0 TFLOPS at 8:1 ratio exceeds the Rubin's 260.0 TFLOPS at 2:1, though the ratio difference complicates direct comparison. The MI300 also has a higher base clock (1000 MHz versus 700 MHz) and a far lower power requirement. At 600 W versus 2300 W, the MI300 draws 74% less power than the Rubin. Its suggested power supply of 1000 W is 1700 W lower than the Rubin's 2700 W requirement. For data center deployments where power density and cooling are limiting factors, the MI300 presents a much lighter infrastructure burden.

The MI300 also offers a more standard physical form factor: a PCIe 5.0 x16 card with defined dimensions of 267 mm by 111 mm, using conventional 2x 8-pin power connectors. The Rubin uses an SXM Module slot width with no listed dimensions or power connector details, indicating a different integration path.

Neither card has benchmark scores in the database, and both sit at the 50th percentile against all GPUs. This means the performance conclusions here are derived entirely from specification data, not from measured workloads. The average benchmark score of 0 for both parts further confirms the absence of empirical test results.

In summary, the Rubin GPU is the specification leader for compute density, memory capacity, and raw throughput. The MI300 is the more power-efficient and conventionally packaged accelerator. Organizations prioritizing maximum FP32 performance, memory bandwidth, and tensor core availability should favor the Rubin. Organizations constrained by power budgets or requiring a standard PCIe card form factor should consider the MI300. The data does not support a universal recommendation; it supports a workload-specific one.

Specification Differences

The following fields differ between the AMD Radeon Instinct MI300 and the NVIDIA Rubin GPU:

• Chip: Aqua Vanjaram (AMD) versus GR100 (NVIDIA)
• Architecture: CDNA 3.0 (AMD) versus Rubin (NVIDIA)
• Generation: Radeon Instinct (MIx) versus Server Rubin (Rxx)
• Process node: 5 nm (AMD) versus 3 nm (NVIDIA)
• Transistors: 153,000 million (AMD) versus 336,000 million (NVIDIA)
• Die size: 1017 mm² (AMD) versus 1456 mm² (NVIDIA)
• Transistor density: 150.4M per mm² (AMD) versus 230.8M per mm² (NVIDIA)
• Base clock: 1000 MHz (AMD) versus 700 MHz (NVIDIA)
• Boost clock: 1700 MHz (AMD) versus 2267 MHz (NVIDIA)
• Memory clock: 1600 MHz, 6.4 Gbps effective (AMD) versus 2695 MHz, 10.8 Gbps effective (NVIDIA)
• Memory size: 128 GB (AMD) versus 288 GB (NVIDIA)
• Memory type: HBM3 (AMD) versus HBM4 (NVIDIA)
• Memory bus width: 8192 bit (AMD) versus 16384 bit (NVIDIA)
• Memory bandwidth: 6.55 TB/s (AMD) versus 22.1 TB/s (NVIDIA)
• Shading units: 14,080 (AMD) versus 28,672 (NVIDIA)
• TMUs: 880 (AMD) versus 896 (NVIDIA)
• ROPs: 0 (AMD) versus 24 (NVIDIA)
• Tensor cores: none listed (AMD) versus 896 (NVIDIA)
• Pixel rate: 0 MPixel/s (AMD) versus 54.41 GPixel/s (NVIDIA)
• Texture rate: 1,496.0 GTexel/s (AMD) versus 2,031.2 GTexel/s (NVIDIA)
• FP32: 47.87 TFLOPS (AMD) versus 130.0 TFLOPS (NVIDIA)
• FP16: 383.0 TFLOPS at 8:1 (AMD) versus 260.0 TFLOPS at 2:1 (NVIDIA)
• TDP: 600 W (AMD) versus 2300 W (NVIDIA)
• Slot width: not listed (AMD) versus SXM Module (NVIDIA)
• Power connectors: 2x 8-pin (AMD) versus none listed (NVIDIA)
• Suggested PSU: 1000 W (AMD) versus 2700 W (NVIDIA)
• Bus interface: PCIe 5.0 x16 (AMD) versus PCIe 6.0 x16 (NVIDIA)
• DirectX API: not listed (AMD) versus N/A (NVIDIA)
• OpenGL API: not listed (AMD) versus N/A (NVIDIA)
• Vulkan API: not listed (AMD) versus N/A (NVIDIA)
• Dimensions: 267 mm by 111 mm (AMD) versus not listed (NVIDIA)
• Production status: not listed (AMD) versus Active (NVIDIA)
• Release date: 2023-01-03 (AMD) versus 2025-12-31 (NVIDIA)
• Predecessor: FirePro Data Center (AMD) versus Server Blackwell (NVIDIA)