AMD Instinct MI300X vs NVIDIA GeForce RTX 4090 Mobile Comparison

Head-to-Head Benchmarks

The database contains one directly comparable measurement between these two accelerators: the Geekbench OpenCL score. In this test, the AMD Instinct MI300X records a score of 317,994, while the NVIDIA GeForce RTX 4090 Mobile scores 180,831. The delta between them is a decisive 75.9% advantage for the AMD part. This is not a marginal lead; the MI300X delivers roughly three-quarters more compute throughput in this OpenCL workload.

Context from the nearest rivals section reinforces the scale of this result. The MI300X sits at the 100th percentile of all GPUs in the database, meaning no other recorded accelerator outperforms it in the aggregate benchmark set. Its average benchmark score is identical to its single OpenCL result, 317,994, because that is the only test recorded for it. The RTX 4090 Mobile, by contrast, sits at the 84th percentile, with an average benchmark score of 43,667 across nine different tests. That average is dragged down by its low DirectX and 2D scores, but even its strongest individual result, the OpenCL score of 180,831, remains far behind the MI300X.

Comparing the MI300X to its nearest rivals shows that it is competitive at the very top of the compute hierarchy. It trails the NVIDIA B200 by 8% and the NVIDIA H200 NVL by 5%, but it leads the NVIDIA L40S by 7.5% and the NVIDIA RTX 6000 Ada Generation by 10.7%. These deltas place the MI300X in a narrow band among the fastest data-center accelerators, with only two recorded parts clearly ahead of it.

The RTX 4090 Mobile, on the other hand, is clustered with a very different set of competitors. Its nearest rivals include the NVIDIA Quadro M6000 (0.8% faster), the GeForce RTX 5050 Mobile (0.9% faster), the Quadro M6000 24 GB (0.9% faster), and the RTX A6000 (0.9% slower). This grouping shows that the mobile part, despite its high position in the GeForce laptop lineup, occupies a mid-tier position in the overall database. It is not in the same performance class as the MI300X, nor is it near the top of the absolute rankings.

The single head-to-head test is the only direct comparison available, but the percentile data tells the same story. The MI300X is a top-100-percentile part, while the RTX 4090 Mobile is an 84th-percentile part. The performance gap between them is substantial and consistent across both the direct benchmark and the broader ranking context.

The Verdict

The data indicates a clear separation in intended use cases. The AMD Instinct MI300X is a data-center compute accelerator with a recorded OpenCL score of 317,994, placing it at the 100th percentile of all GPUs. It is designed for workloads where raw compute throughput, massive memory capacity, and high bandwidth are the dominant requirements. Its nearest rivals are all NVIDIA data-center or professional parts, and it outperforms most of them.

The NVIDIA GeForce RTX 4090 Mobile is a laptop GPU with a peak OpenCL score of 180,831, which is 75.9% lower than the MI300X. Its average benchmark score of 43,667 reflects a mix of workloads, including DirectX and 2D tests, where it shows modest results. It sits at the 84th percentile, surrounded by older professional GPUs and newer mobile parts like the RTX 5050 Mobile.

For users selecting between these two, the choice is not about one being better in all respects, but about which workload profile matches the hardware. The MI300X is the obvious pick for server-side compute tasks where the 192 GB memory pool and 5.32 TB/s bandwidth are critical, and where the 750 W power draw is acceptable. The RTX 4090 Mobile is intended for portable systems where the 120 W power envelope and integrated form factor are mandatory, and where the 16 GB GDDR6 memory is sufficient.

There is no overlap in their design goals. The MI300X has no display outputs, no DirectX support, and a power connector rating of none, as it is an OAM module. The RTX 4090 Mobile has portable-device-dependent display outputs, supports DirectX 12 Ultimate, and is an IGP. The data shows that the MI300X is a specialized compute engine, while the RTX 4090 Mobile is a general-purpose graphics processor for laptops. Neither part outperforms the other in the other's domain, because they are not designed to compete in the same domain.

FAQ

Q: Which GPU has the higher Geekbench OpenCL score?

A: The AMD Instinct MI300X scores 317,994, which is 75.9% higher than the NVIDIA GeForce RTX 4090 Mobile's 180,831.

Q: How does the MI300X compare to other data-center accelerators?

A: The MI300X is 7.5% ahead of the NVIDIA L40S and 10.7% ahead of the NVIDIA RTX 6000 Ada Generation, but it is 5% behind the NVIDIA H200 NVL and 8% behind the NVIDIA B200.

Q: What is the RTX 4090 Mobile's percentile ranking?

A: It sits at the 84th percentile of all GPUs in the database, with an average benchmark score of 43,667 across nine tests.

Q: Does the MI300X support DirectX or Vulkan?

A: No. The database lists DirectX, OpenGL, and Vulkan as N/A for the MI300X. The RTX 4090 Mobile supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4.

Q: What are the memory specifications for each part?

A: The MI300X has 192 GB of HBM3 on an 8192-bit bus with 5.32 TB/s bandwidth. The RTX 4090 Mobile has 16 GB of GDDR6 on a 256-bit bus with 576.0 GB/s bandwidth.

Q: Which part has more shading units?

A: The MI300X has 19,456 shading units, while the RTX 4090 Mobile has 9,728, exactly half as many.

Specification Differences

The two parts differ on nearly every recorded specification. The MI300X uses an AMD Aqua Vanjaram chip with CDNA 3.0 architecture, while the RTX 4090 Mobile uses an NVIDIA AD103 chip with Ada Lovelace architecture. Both are built on a 5 nm process at TSMC, but the transistor counts differ dramatically: the MI300X has 153,000 million transistors on a 1017 mm² die, while the RTX 4090 Mobile has 45,900 million transistors on a 379 mm² die. The transistor density also differs, with the MI300X at 150.4M per mm² and the RTX 4090 Mobile at 121.1M per mm².

Clock speeds are different in both base and boost. The MI300X runs at 1000 MHz base and 2100 MHz boost, while the RTX 4090 Mobile runs at 1335 MHz base and 1695 MHz boost. Memory clocks are also distinct: the MI300X uses 1300 MHz with 5.2 Gbps effective, while the RTX 4090 Mobile uses 2250 MHz with 18 Gbps effective.

Compute resources differ across the board. The MI300X has 19,456 shading units, 1,216 TMUs, and 0 ROPs. The RTX 4090 Mobile has 9,728 shading units, 304 TMUs, and 112 ROPs. The RTX 4090 Mobile also has 76 ray-tracing cores and 304 tensor cores, while the MI300X has no recorded RT or tensor cores. Pixel rate is 0 MPixel/s for the MI300X versus 189.8 GPixel/s for the RTX 4090 Mobile. Texture rate is 2,553.6 GTexel/s for the MI300X versus 515.3 GTexel/s for the RTX 4090 Mobile.

FP32 and FP16 compute are both 81.72 TFLOPS for the MI300X, while the RTX 4090 Mobile delivers 32.98 TFLOPS in both. Power draw is 750 W for the MI300X versus 120 W for the RTX 4090 Mobile. The MI300X is an OAM module with no power connectors and a suggested PSU of 1150 W, while the RTX 4090 Mobile is an IGP with no power connectors and no suggested PSU. Bus interfaces differ: PCIe 5.0 x16 for the MI300X, PCIe 4.0 x16 for the RTX 4090 Mobile. Display outputs are absent on the MI300X and portable-device-dependent on the RTX 4090 Mobile.

Architecture Differences

The MI300X is built on CDNA 3.0, AMD's compute-focused architecture, while the RTX 4090 Mobile uses Ada Lovelace, NVIDIA's graphics-focused architecture. This distinction is visible in the feature set. The MI300X has no display outputs, no graphics API support, and no ROPs, confirming that it is purely a compute accelerator. The RTX 4090 Mobile has display outputs, supports DirectX 12 Ultimate and Vulkan 1.4, and includes ray-tracing and tensor cores, confirming its role as a general-purpose graphics processor.

Memory architecture also diverges sharply. The MI300X uses HBM3 with an 8192-bit bus, which explains its 5.32 TB/s bandwidth. The RTX 4090 Mobile uses GDDR6 with a 256-bit bus, yielding 576.0 GB/s. The MI300X's memory capacity of 192 GB is 12 times the RTX 4090 Mobile's 16 GB. This capacity and bandwidth combination is intended for large model inference and training workloads, where the RTX 4090 Mobile's memory would be a limiting factor.

The transistor counts reflect different design philosophies. The MI300X uses 153,000 million transistors across a 1017 mm² die, with a density of 150.4M per mm². The RTX 4090 Mobile uses 45,900 million transistors on a 379 mm² die, with a density of 121.1M per mm². The MI300X is a massive chip, more than 2.5 times the die area of the RTX 4090 Mobile, and it uses that area for more shading units, more TMUs, and a much wider memory bus.

The absence of RT and tensor cores on the MI300X is notable. The RTX 4090 Mobile includes 76 RT cores and 304 tensor cores, which are used for ray tracing and AI acceleration in graphics workloads. The MI300X does not record these features, indicating that its compute model relies on the massive FP32/FP16 throughput of its 19,456 shading units instead of specialized tensor hardware.

Power and physical format differences also reflect the design split. The MI300X consumes 750 W and requires a 1150 W PSU, while the RTX 4090 Mobile consumes 120 W. The MI300X is an OAM module, designed for server chassis with dedicated cooling, while the RTX 4090 Mobile is an IGP, soldered into laptops. Release dates differ by roughly 11 months: the RTX 4090 Mobile launched in January 2023, while the MI300X launched in December 2023. The RTX 4090 Mobile has a predecessor in GeForce 30 Mobile and a successor in GeForce 50 Mobile, while the MI300X's predecessor is Radeon Instinct and no successor is recorded.