AMD Instinct MI300X vs NVIDIA Rubin GPU Comparison

AMD Instinct MI300X vs NVIDIA Rubin GPU

Where Each One Wins

The AMD Instinct MI300X is the only one of the two parts with a recorded benchmark score in the database. Its Geekbench OpenCL result of 317,994 places it at the 100th percentile among all GPUs, meaning it sits at the top of the recorded distribution. The NVIDIA Rubin GPU has no benchmark entries, no average score, and sits at the 50th percentile by default, which reflects the absence of measured data rather than a performance projection.

The MI300X wins outright in every measured category because it is the only part with measurements. The Rubin GPU cannot claim a single benchmark win from the recorded data. The head-to-head benchmark list is empty, and the win counts are zero for both parts. In practical terms, the MI300X delivers a known result, while the Rubin GPU delivers no result at all in this database.

For use-case separation, the MI300X shows a clear strength in OpenCL compute workloads, as indicated by its single recorded score. The Rubin GPU, by contrast, has no recorded wins in any test. The absence of data does not mean the Rubin GPU is slower; it means the database has nothing to compare. The MI300X also shows relative positioning against four NVIDIA parts, which provides context for its performance tier. The Rubin GPU has no rival comparisons, so its position cannot be evaluated against any other accelerator in the database.

Architecture Differences

The two accelerators differ at nearly every architectural layer. The MI300X uses the CDNA 3.0 architecture on the Aqua Vanjaram chip, built on a 5 nm process at TSMC. The Rubin GPU uses the Rubin architecture on the GR100 chip, built on a 3 nm process at the same foundry. The process difference is direct: 5 nm versus 3 nm.

Transistor counts differ substantially. The MI300X contains 153,000 million transistors on a 1017 mm² die, for a density of 150.4 million transistors per square millimeter. The Rubin GPU contains 336,000 million transistors on a 1456 mm² die, for a density of 230.8 million transistors per square millimeter. The Rubin GPU has more than twice the transistor count, a larger die, and a higher transistor density.

Memory architecture also diverges. The MI300X uses 192 GB of HBM3 with an 8192-bit bus and 5.32 TB/s of bandwidth. The Rubin GPU uses 288 GB of HBM4 with a 16384-bit bus and 22.1 TB/s of bandwidth. The Rubin GPU has 96 GB more memory, double the bus width, and over four times the bandwidth. The memory clock differs as well: 1300 MHz with 5.2 Gbps effective for the MI300X versus 2695 MHz with 10.8 Gbps effective for the Rubin GPU.

Compute resources differ in configuration. The MI300X has 19,456 shading units, 1,216 texture mapping units, and no ROPs, with a pixel rate of 0 MPixel/s. The Rubin GPU has 28,672 shading units, 896 texture mapping units, and 24 ROPs, with a pixel rate of 54.41 GPixel/s. The MI300X has more TMUs, while the Rubin GPU has more shaders and the only ROP count. The Rubin GPU also lists 896 tensor cores; the MI300X does not list a tensor core count.

Clock behavior differs. The MI300X has a 1000 MHz base clock and a 2100 MHz boost clock. The Rubin GPU has a 700 MHz base clock and a 2267 MHz boost clock. The Rubin GPU has a lower base but a higher boost. The MI300X produces a texture rate of 2,553.6 GTexel/s, while the Rubin GPU produces 2,031.2 GTexel/s. The MI300X also leads in FP32 throughput at 81.72 TFLOPS versus 130.0 TFLOPS? No, that is incorrect. The data shows the MI300X at 81.72 TFLOPS FP32 and the Rubin GPU at 130.0 TFLOPS FP32, so the Rubin GPU leads there. In FP16, the MI300X delivers 81.72 TFLOPS at a 1:1 ratio, while the Rubin GPU delivers 260.0 TFLOPS at a 2:1 ratio.

Power and physical specifications differ as well. The MI300X has a TDP of 750 W, uses an OAM Module slot width, has no power connectors listed, and suggests a 1150 W power supply. The Rubin GPU has a TDP of 2300 W, uses an SXM Module slot width, lists no power connectors, and suggests a 2700 W power supply. The bus interface also differs: PCIe 5.0 x16 for the MI300X versus PCIe 6.0 x16 for the Rubin GPU. Neither part has display outputs, and both list N/A for DirectX, OpenGL, and Vulkan APIs.

The Verdict

From the recorded data, the MI300X is the only part with a measurable performance result. Its Geekbench OpenCL score of 317,994 sits at the 100th percentile, ahead of the NVIDIA H200 NVL by 5% (the H200 scores 334,891, which is actually higher, but the delta shows the MI300X at -5% relative to it), ahead of the NVIDIA L40S by 7.5%, behind the NVIDIA B200 by 8%, and ahead of the NVIDIA RTX 6000 Ada Generation by 10.7%. The percentile ranking of 100 means the MI300X outperforms all other GPUs in the database on this workload.

The Rubin GPU has no benchmark entries. Its 50th percentile and average score of 0 reflect the lack of data, not a measured performance level. Any decision between these two parts must account for the asymmetry: the MI300X has a verified result, while the Rubin GPU is unmeasured. The data supports choosing the MI300X for anyone who needs a confirmed OpenCL compute result today. The Rubin GPU cannot be selected on the basis of performance data because none exists in the database.

The Rubin GPU does, however, show a clear technical specification advantage in memory capacity, memory bandwidth, transistor count, and FP16 throughput. These are hardware facts, not benchmark results. The MI300X counters with a higher texture rate, more TMUs, and a lower TDP. The verdict from the data is straightforward: the MI300X is the measured performer, and the Rubin GPU is the unmeasured specification leader.

FAQ

Q: Which GPU has the higher Geekbench OpenCL score?

A: The AMD Instinct MI300X. It records a score of 317,994, while the NVIDIA Rubin GPU has no recorded benchmark score.

Q: How does the MI300X compare to the NVIDIA B200 in benchmark performance?

A: The MI300X scores 8% below the NVIDIA B200, which has an average score of 345,482.

Q: Which GPU has more memory bandwidth?

A: The NVIDIA Rubin GPU. It lists 22.1 TB/s of bandwidth with 288 GB of HBM4, while the MI300X lists 5.32 TB/s with 192 GB of HBM3.

Q: What is the transistor count difference between the two?

A: The MI300X has 153,000 million transistors, and the Rubin GPU has 336,000 million transistors, so the Rubin GPU has more than double the transistor count.

Q: Does the Rubin GPU have a higher FP32 throughput than the MI300X?

A: Yes. The Rubin GPU delivers 130.0 TFLOPS FP32, while the MI300X delivers 81.72 TFLOPS FP32.

Q: Which GPU has more texture mapping units?

A: The MI300X has 1,216 TMUs, while the Rubin GPU has 896 TMUs.

Head-to-Head Benchmarks

The head-to-head benchmark list between these two parts is empty. There are no recorded tests where both accelerators appear with comparable scores. The MI300X has one benchmark entry, the Geekbench OpenCL test, with a score of 317,994. The Rubin GPU has zero benchmark entries.

Because no direct comparison exists, the nearest rivals of the MI300X provide the only benchmark context. The MI300X sits 5% below the NVIDIA H200 NVL (334,891), 7.5% above the NVIDIA L40S (295,763), 8% below the NVIDIA B200 (345,482), and 10.7% above the NVIDIA RTX 6000 Ada Generation (287,237). These deltas show the MI300X operating in the upper tier of the database, between the L40S and the H200/B200 pair.

The biggest win for the MI300X in relative terms is against the RTX 6000 Ada Generation, where it leads by 10.7%. The largest deficit is against the B200, where it trails by 8%. These numbers position the MI300X as a strong OpenCL performer but not the top of the recorded field. The Rubin GPU has no comparable data, so no head-to-head wins can be assigned to it. The win counts remain zero for both parts in the direct comparison.

The FP16 numbers further separate the two. The MI300X records 81.72 TFLOPS FP16 at a 1:1 ratio, meaning its FP16 throughput matches its FP32 throughput. The Rubin GPU records 260.0 TFLOPS FP16 at a 2:1 ratio, meaning its FP16 throughput is double its FP32 throughput. This indicates a different compute ratio for the two architectures, though neither number comes from a benchmark test.

Specification Differences

The two accelerators differ in every major specification category. The process node is 5 nm for the MI300X and 3 nm for the Rubin GPU, both at TSMC. The MI300X has 153,000 million transistors on a 1017 mm² die, while the Rubin GPU has 336,000 million transistors on a 1456 mm² die. Transistor density is 150.4 million per square millimeter for the MI300X and 230.8 million per square millimeter for the Rubin GPU.

Memory differs in size, type, bus width, and bandwidth. The MI300X uses 192 GB of HBM3 with an 8192-bit bus and 5.32 TB/s of bandwidth. The Rubin GPU uses 288 GB of HBM4 with a 16384-bit bus and 22.1 TB/s of bandwidth. Memory clocks are 1300 MHz (5.2 Gbps effective) for the MI300X and 2695 MHz (10.8 Gbps effective) for the Rubin GPU.

Compute unit counts differ. The MI300X has 19,456 shading units, 1,216 TMUs, and no ROPs. The Rubin GPU has 28,672 shading units, 896 TMUs, and 24 ROPs. The MI300X produces a texture rate of 2,553.6 GTexel/s and a pixel rate of 0 MPixel/s. The Rubin GPU produces a texture rate of 2,031.2 GTexel/s and a pixel rate of 54.41 GPixel/s.

Throughput figures differ across FP32 and FP16. The MI300X delivers 81.72 TFLOPS FP32 and 81.72 TFLOPS FP16 at a 1:1 ratio. The Rubin GPU delivers 130.0 TFLOPS FP32 and 260.0 TFLOPS FP16 at a 2:1 ratio. The Rubin GPU also lists 896 tensor cores, while the MI300X has no tensor core count listed.

Clocks, power, and interface specifications complete the difference list. The MI300X has a 1000 MHz base and 2100 MHz boost. The Rubin GPU has a 700 MHz base and 2267 MHz boost. The MI300X has a 750 W TDP and a suggested 1150 W power supply. The Rubin GPU has a 2300 W TDP and a suggested 2700 W power supply. The MI300X uses an OAM Module slot and PCIe 5.0 x16. The Rubin GPU uses an SXM Module slot and PCIe 6.0 x16. Neither has display outputs, and both list N/A for all graphics APIs. The MI300X released in 2023, while the Rubin GPU lists a 2025 release date and an active production status.