AMD Radeon PRO W6400 vs NVIDIA GeForce RTX 4090 Mobile Comparison

FAQ

Q: How does the NVIDIA GeForce RTX 4090 Mobile compare to the AMD Radeon PRO W6400 in raw compute performance?

A: The RTX 4090 Mobile delivers 32.98 TFLOPS of FP32 performance, while the Radeon PRO W6400 offers 3.565 TFLOPS. That is a 9.25x difference in theoretical peak compute, which shows up clearly in benchmark scores.

Q: Which GPU has the higher memory bandwidth?

A: The RTX 4090 Mobile has 576.0 GB/s of bandwidth from its 16 GB GDDR6 memory on a 256-bit bus. The Radeon PRO W6400 has 128.0 GB/s from 4 GB GDDR6 on a 64-bit bus, exactly one-quarter of the bandwidth.

Q: What is the performance gap in Geekbench OpenCL?

A: The RTX 4090 Mobile scores 180,831 versus 35,027 for the Radeon PRO W6400, a delta of 416.3%. This is the largest margin in any shared benchmark.

Q: Are both GPUs compatible with DirectX 12 Ultimate?

A: Yes, both list DirectX 12 Ultimate (12_2) support. They also share OpenGL 4.6 and Vulkan 1.4 API support, so API-level compatibility is identical.

Q: Which GPU has a higher transistor density?

A: The RTX 4090 Mobile uses TSMC's 5 nm process with 121.1M transistors per mm², while the Radeon PRO W6400 uses 6 nm with 50.5M per mm². The NVIDIA chip packs more than twice the density.

Q: What is the production status of each GPU?

A: The RTX 4090 Mobile is listed as Active production, while the Radeon PRO W6400 is marked End-of-life. The AMD card was released earlier, in January 2022, versus January 2023 for the NVIDIA part.

Architecture Differences

The RTX 4090 Mobile is built on NVIDIA's Ada Lovelace architecture using the AD103 chip, fabricated on TSMC's 5 nm process. The die measures 379 mm² and contains 45,900 million transistors, yielding a transistor density of 121.1M per mm². This is a massive, high-complexity design aimed at maximum throughput in mobile form.

The Radeon PRO W6400 uses AMD's RDNA 2.0 architecture with the Navi 24 chip, on TSMC's 6 nm process. Its die is 107 mm² with 5,400 million transistors, giving a much lower density of 50.5M per mm². This is a small, efficiency-focused chip designed for entry-level professional workloads.

Compute resources differ starkly. The RTX 4090 Mobile has 9,728 shading units, 304 TMUs, 112 ROPs, 76 RT cores, and 304 tensor cores. The Radeon PRO W6400 has 768 shading units, 48 TMUs, 32 ROPs, and 12 RT cores, with no tensor cores. The NVIDIA GPU has roughly 12.7x more shading units and 6.3x more TMUs.

Memory architecture is a major differentiator. The RTX 4090 Mobile uses 16 GB of GDDR6 on a 256-bit bus with 576.0 GB/s bandwidth, while the W6400 has 4 GB on a 64-bit bus with 128.0 GB/s. The RTX 4090 Mobile also runs its memory at 18 Gbps effective versus 16 Gbps on the AMD card.

Clock behavior differs as well. The Radeon PRO W6400 has a higher base clock of 2039 MHz and boost of 2321 MHz, compared to 1335 MHz base and 1695 MHz boost on the RTX 4090 Mobile. However, the NVIDIA chip's far larger execution resources more than compensate for the lower clocks.

Power and physical design reflect their different missions. The RTX 4090 Mobile is rated at 120 W TDP and is an IGP (integrated graphics package), while the W6400 draws 50 W, is single-slot, and has no power connectors, just like the RTX card. The W6400 lists a suggested PSU of 250 W, while the RTX 4090 Mobile has no suggested PSU listed.

The Verdict

If raw performance is the priority, the RTX 4090 Mobile wins decisively. In the two shared benchmarks, Geekbench OpenCL and Vulkan, it beats the Radeon PRO W6400 by 416.3% and 334.7% respectively. Its 84th percentile among all GPUs versus the W6400's 80th percentile understates the gap because the AMD card's percentile is buoyed by its efficiency, not its absolute speed.

The RTX 4090 Mobile is the pick for anyone running compute-heavy workloads, large datasets, or demanding 3D rendering where 16 GB of VRAM and 576.0 GB/s bandwidth matter. Its 32.98 TFLOPS FP32 and 32.98 TFLOPS FP16 (1:1) make it suitable for AI inference and high-precision compute tasks.

The Radeon PRO W6400 is for constrained, low-power environments. At 50 W TDP with no power connectors, it fits into systems where the RTX 4090 Mobile's 120 W draw would be impractical. It has a higher base and boost clock, which can help in latency-sensitive, lightly threaded workloads, but its 3.565 TFLOPS FP32 and 7.130 TFLOPS FP16 (2:1) are a fraction of the NVIDIA part's capabilities.

The RTX 4090 Mobile is also the more future-proof option, being Active production with a successor (GeForce 50 Mobile) already defined. The W6400 is End-of-life with no successor listed. For professional buyers, the NVIDIA card offers longer availability and better long-term support prospects.

Specification Differences

| Specification | NVIDIA GeForce RTX 4090 Mobile | AMD Radeon PRO W6400 |

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

| Process node | 5 nm | 6 nm |

| Transistors | 45,900 million | 5,400 million |

| Die size | 379 mm² | 107 mm² |

| Transistor density | 121.1M / mm² | 50.5M / mm² |

| Base clock | 1335 MHz | 2039 MHz |

| Boost clock | 1695 MHz | 2321 MHz |

| Memory clock | 2250 MHz (18 Gbps effective) | 2000 MHz (16 Gbps effective) |

| Memory size | 16 GB | 4 GB |

| Memory bus | 256 bit | 64 bit |

| Memory bandwidth | 576.0 GB/s | 128.0 GB/s |

| Shading units | 9728 | 768 |

| TMUs | 304 | 48 |

| ROPs | 112 | 32 |

| RT cores | 76 | 12 |

| Tensor cores | 304 | None |

| Pixel rate | 189.8 GPixel/s | 74.27 GPixel/s |

| Texture rate | 515.3 GTexel/s | 111.4 GTexel/s |

| FP32 | 32.98 TFLOPS | 3.565 TFLOPS |

| FP16 | 32.98 TFLOPS (1:1) | 7.130 TFLOPS (2:1) |

| TDP | 120 W | 50 W |

| Slot width | IGP | Single-slot |

| Bus interface | PCIe 4.0 x16 | PCIe 4.0 x4 |

| Display outputs | Portable Device Dependent | 2x DisplayPort 1.4a |

| Release date | 2023-01-02 | 2022-01-18 |

| Production status | Active | End-of-life |

Head-to-Head Benchmarks

Only two benchmark tests cover both GPUs in the database: Geekbench OpenCL and Geekbench Vulkan. The RTX 4090 Mobile wins both.

In Geekbench OpenCL, the RTX 4090 Mobile scores 180,831 against 35,027 for the Radeon PRO W6400. This is a 416.3% delta, the single largest performance gap recorded between these two parts. The NVIDIA GPU's FP32 throughput, 32.98 TFLOPS versus 3.565 TFLOPS, explains most of this gap, with memory bandwidth also playing a role.

In Geekbench Vulkan, the margin narrows but remains enormous. The RTX 4090 Mobile scores 170,774, while the W6400 manages 39,286, a 334.7% difference. Vulkan workloads tend to scale with shading unit count, and the RTX 4090 Mobile's 9,728 shading units overwhelm the W6400's 768.

The RTX 4090 Mobile's average benchmark score across all tests in the database is 43,667, placing it in the 84th percentile of all GPUs. Its nearest rivals include the NVIDIA RTX A6000 (44,075, 0.9% ahead) and the Quadro M6000 (43,301, 0.8% behind), showing it sits in strong company.

The Radeon PRO W6400's average score is 37,157, in the 80th percentile. Its nearest rival, the AMD Radeon RX Vega 56, scores 37,507, which is 0.9% ahead. The NVIDIA Tesla P4 and GeForce RTX 4070 also sit within 1.3% of the W6400, meaning the AMD card is competitive with mid-range parts from other families despite its low power draw.

The RTX 4090 Mobile has additional benchmark data that the W6400 lacks, including Passmark DirectX 10, 11, 12, 9, G2D, G3D, and GPU compute scores. Its Passmark G3D score is 27,212 and GPU compute is 12,347, which are not comparable to the AMD card since those tests were not run on it.

Where Each One Wins

The RTX 4090 Mobile wins everywhere performance is measured. In both shared benchmarks, it leads by over 300%. Its 16 GB VRAM capacity is four times the W6400's 4 GB, which matters for large textures, machine learning models, or multi-display professional work. The 576.0 GB/s bandwidth supports high-resolution rendering and data-heavy compute tasks without bottlenecking.

The RTX 4090 Mobile also wins on feature set. It has 304 tensor cores for AI acceleration, which the W6400 lacks entirely. Its FP16 performance is 32.98 TFLOPS at a 1:1 ratio with FP32, whereas the W6400's FP16 is 7.130 TFLOPS at a 2:1 ratio, meaning the NVIDIA card is both faster and more consistent across precision levels.

The Radeon PRO W6400 wins on power efficiency and physical footprint. At 50 W TDP, it draws less than half the power of the RTX 4090 Mobile's 120 W. It is a single-slot card with no power connectors and a 250 W suggested PSU, making it suitable for small form factor or low-power workstations. The RTX 4090 Mobile, being an IGP, requires a laptop or embedded solution to host it.

The W6400 also has higher clocks, with a 2321 MHz boost versus 1695 MHz on the RTX 4090 Mobile. In workloads that are latency-bound or depend on single-threaded GPU execution, the higher clock could provide a relative advantage, though the NVIDIA card's massive parallel resources will still dominate in throughput tests.

The W6400's PCIe 4.0 x4 interface is narrower than the RTX 4090 Mobile's x16, which limits data transfer rates between GPU and CPU. For professional applications that stream large datasets, the RTX 4090 Mobile's wider bus is a clear advantage.

For a low-power, entry-level professional card with DisplayPort 1.4a outputs and no external power requirement, the Radeon PRO W6400 is the practical choice. For any workload where performance matters, the RTX 4090 Mobile is the only rational selection based on the recorded data.