AMD Instinct MI355X vs NVIDIA GeForce RTX 4090 Mobile Comparison

The Verdict

The recorded data presents two fundamentally different devices with almost no overlap in intended use. The AMD Instinct MI355X is a compute-focused accelerator with no display outputs, built for data center workloads, while the NVIDIA GeForce RTX 4090 Mobile is a portable graphics processor designed for laptops. The MI355X carries a 50th percentile rank among all GPUs in the database, though it has no recorded benchmark scores. The RTX 4090 Mobile sits at the 84th percentile with an average benchmark score of 43,667, placing it slightly ahead of the NVIDIA Quadro M6000 by 0.8% and marginally behind the NVIDIA RTX A6000 by 0.9%. For users needing a mobile graphics solution with established DirectX, OpenGL, and Vulkan support, the RTX 4090 Mobile is the only viable option. For compute-heavy environments requiring massive memory capacity and bandwidth, the MI355X is the clear choice based on its specifications, despite lacking benchmark validation.

Architecture Differences

The two processors come from different architectural lineages. The AMD Instinct MI355X uses the CDNA 4.0 architecture built on a 3 nm TSMC process, packing 185,000 million transistors onto a 2380 mm² die. This yields a transistor density of 77.7 million transistors per square millimeter. The NVIDIA GeForce RTX 4090 Mobile uses the Ada Lovelace architecture on a 5 nm TSMC process, with 45,900 million transistors on a 379 mm² die, giving a transistor density of 121.1 million per square millimeter. The MI355X has a substantially larger physical footprint, reflecting its data center OAM module form factor.

The MI355X employs the MI350 256CU chip with 16,384 shading units and 1,024 texture mapping units. It has no raster operation units, no ray tracing cores, and no tensor cores listed in the database. The RTX 4090 Mobile uses the AD103 chip with 9,728 shading units, 304 texture mapping units, 112 ROPs, 76 ray tracing cores, and 304 tensor cores. This difference explains why the RTX 4090 Mobile supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4, while the MI355X reports no API support. The MI355X delivers 78.64 TFLOPS for both FP32 and FP16 compute, while the RTX 4090 Mobile delivers 32.98 TFLOPS for both precisions. The MI355X also has no pixel rate, while the RTX 4090 Mobile achieves 189.8 GPixel/s.

Head-to-Head Benchmarks

The database contains no direct head-to-head benchmark results between the MI355X and the RTX 4090 Mobile. However, the RTX 4090 Mobile has extensive benchmark data, while the MI355X has none. The RTX 4090 Mobile scores 180,831 in Geekbench OpenCL and 170,774 in Geekbench Vulkan. Its PassMark results include 173 in DirectX 10, 262 in DirectX 11, 107 in DirectX 12, and 310 in DirectX 9. The 2D graphics score is 984, the 3D graphics score is 27,212, and the GPU compute score is 12,347. The average benchmark score across all tests is 43,667.

The MI355X has zero recorded benchmark scores and zero wins in any head-to-head comparison. The RTX 4090 Mobile also has zero wins in the head-to-head section, but its substantial specification advantages in memory capacity, bandwidth, and compute throughput suggest it would dominate in memory-intensive workloads. The MI355X offers 288 GB of HBM3e memory with an 8,192-bit bus and 8.19 TB/s bandwidth, while the RTX 4090 Mobile offers 16 GB of GDDR6 memory with a 256-bit bus and 576.0 GB/s bandwidth. This gives the MI355X roughly 14.2 times the memory capacity and 14.2 times the bandwidth, though these figures are derived from the recorded data and not from direct testing.

The RTX 4090 Mobile's nearest rivals in the database include the NVIDIA Quadro M6000 with an average score of 43,301 (0.8% faster), the NVIDIA GeForce RTX 5050 Mobile at 43,268 (0.9% faster), the NVIDIA Quadro M6000 24 GB at 43,262 (0.9% faster), and the NVIDIA RTX A6000 at 44,075 (0.9% slower). These comparisons show the RTX 4090 Mobile sitting in a tight cluster of similarly performing GPUs, with only 1.8% separating the slowest rival from the fastest.

FAQ

Q: Does the AMD Instinct MI355X support gaming APIs like DirectX or Vulkan?

A: No. The database lists DirectX, OpenGL, and Vulkan support as "N/A" for the MI355X. It has no display outputs, making it unsuitable for any graphics rendering workload.

Q: How does the memory configuration differ between the two GPUs?

A: The MI355X uses 288 GB of HBM3e memory on an 8,192-bit bus with 8.19 TB/s bandwidth. The RTX 4090 Mobile uses 16 GB of GDDR6 memory on a 256-bit bus with 576.0 GB/s bandwidth.

Q: What is the power consumption difference?

A: The MI355X has a TDP of 1400 W and requires an 1800 W power supply. The RTX 4090 Mobile has a TDP of 120 W and does not list a suggested power supply, reflecting its mobile IGP form factor.

Q: Which GPU has better benchmark performance in the database?

A: Only the RTX 4090 Mobile has recorded benchmarks. It achieves an average score of 43,667 with a 84th percentile rank. The MI355X has no benchmark scores and sits at the 50th percentile.

Q: Are there any ray tracing capabilities on either GPU?

A: The RTX 4090 Mobile includes 76 ray tracing cores. The MI355X lists no ray tracing cores in the database.

Q: What are the physical form factors?

A: The MI355X is an OAM module measuring 102 mm in length and 165 mm in width. The RTX 4090 Mobile is an IGP (integrated graphics processor) with no listed dimensions, designed for portable devices.

Where Each One Wins

The MI355X dominates in raw compute throughput and memory capacity. Its 78.64 TFLOPS FP32 performance is 2.4 times the RTX 4090 Mobile's 32.98 TFLOPS. The 288 GB HBM3e memory with 8.19 TB/s bandwidth provides 18 times the capacity and 14.2 times the bandwidth of the RTX 4090 Mobile's 16 GB GDDR6. The texture rate of 2,457.6 GTexel/s is 4.8 times the RTX 4090 Mobile's 515.3 GTexel/s. The MI355X uses a larger 3 nm node with 185,000 million transistors, and its PCIe 5.0 x16 interface doubles the bandwidth of the RTX 4090 Mobile's PCIe 4.0 x16. This makes the MI355X suited for large-scale compute workloads such as AI training, scientific simulation, and massive data processing, where memory capacity and throughput are the primary constraints.

The RTX 4090 Mobile wins in portability, graphics features, and established software support. It has 76 ray tracing cores and 304 tensor cores, enabling hardware-accelerated ray tracing and AI features. Its DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4 support allow it to run any modern graphics application. The 120 W TDP makes it suitable for laptop integration, while the 189.8 GPixel/s pixel rate and 112 ROPs provide real rasterization capability. Its benchmark data confirms functional performance across multiple test suites, with a 84th percentile ranking. The RTX 4090 Mobile also supports portable device dependent display outputs, making it the only choice for any application requiring visual output. The 5 nm process and higher transistor density of 121.1M per mm² indicate a more compact and power-efficient design.

Specification Differences

The two GPUs differ across nearly every specification field in the database. The MI355X uses a 3 nm process node while the RTX 4090 Mobile uses 5 nm, both from TSMC. Transistor count differs dramatically: 185,000 million versus 45,900 million. Die size spans 2380 mm² versus 379 mm². Transistor density runs 77.7M per mm² versus 121.1M per mm². Base clocks are 1000 MHz versus 1335 MHz, boost clocks are 2400 MHz versus 1695 MHz, and memory clocks are 2000 MHz (8 Gbps effective) versus 2250 MHz (18 Gbps effective). Memory size is 288 GB HBM3e versus 16 GB GDDR6. Bus width is 8,192 bits versus 256 bits. Bandwidth is 8.19 TB/s versus 576.0 GB/s. Shading units count 16,384 versus 9,728. TMUs are 1,024 versus 304. ROPs are 0 versus 112. The RTX 4090 Mobile has 76 RT cores and 304 tensor cores, while the MI355X has none. Pixel rate is 0 versus 189.8 GPixel/s. Texture rate is 2,457.6 versus 515.3 GTexel/s. FP32 and FP16 are 78.64 versus 32.98 TFLOPS. TDP is 1400 W versus 120 W. The MI355X is an OAM module with no power connectors and an 1800 W suggested PSU; the RTX 4090 Mobile is an IGP with no power connectors and no PSU requirement. Bus interface is PCIe 5.0 x16 versus PCIe 4.0 x16. Display outputs are absent versus portable device dependent. API support is entirely absent versus full DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4. Release dates are 2025-06-11 versus 2023-01-02. The MI355X has no production status, while the RTX 4090 Mobile is marked active. Neither device has a launch MSRP in the database.