AMD Instinct MI455X vs NVIDIA GeForce RTX 4090 D Comparison

The Verdict

The database records two fundamentally different accelerators. The AMD Instinct MI455X is a compute-focused module with a 50th percentile standing across all GPUs, while the NVIDIA GeForce RTX 4090 D sits at the 98th percentile. The MI455X targets high-throughput compute workloads with massive memory capacity and bandwidth, while the RTX 4090 D is an end-of-life consumer-grade graphics card with display outputs and a full DirectX 12 Ultimate feature set. For raw compute density and memory-bound tasks, the MI455X is the clear choice. For any workload requiring rendering, display output, or software rasterization, the RTX 4090 D is the only option with functional graphics pipelines.

Architecture Differences

The AMD Instinct MI455X uses the CDNA 5.0 architecture built on a 2 nm process at TSMC, with a die size of 2990 mm² and 320,000 million transistors. The transistor density is 107.0M per mm². The chip is the MI450 256CU, belonging to the Instinct (MIx) generation. It has 32768 shading units and 1024 texture mapping units, but zero raster operation units. The pixel rate is recorded as 0 MPixel/s, and the texture rate is 2,457.6 GTexel/s. The FP32 and FP16 performance are both 157.3 TFLOPS with a 1:1 ratio. The memory subsystem uses 432 GB of HBM4 on a 24576-bit bus, delivering 23.3 TB/s of bandwidth. The memory clock is 1900 MHz with 7.6 Gbps effective. The base clock is 1000 MHz and boost clock is 2400 MHz. The module uses a PCIe 6.0 x16 interface and has no display outputs. It has no power connectors and a suggested PSU of 2700 W, with a TDP of 2300 W. The slot width is described as EAM Module. No DirectX, OpenGL, or Vulkan API support is recorded.

The NVIDIA GeForce RTX 4090 D uses the Ada Lovelace architecture on a 5 nm TSMC process, with a die size of 609 mm² and 76,300 million transistors. The transistor density is 125.3M per mm². It has 14592 shading units, 456 TMUs, and 176 ROPs, with 114 RT cores and 456 tensor cores. The pixel rate is 443.5 GPixel/s and texture rate is 1,149.1 GTexel/s. FP32 and FP16 both reach 73.54 TFLOPS with a 1:1 ratio. Memory is 24 GB of GDDR6X on a 384-bit bus with 1.01 TB/s bandwidth. The memory clock is 1313 MHz with 21 Gbps effective. Base clock is 2280 MHz and boost is 2520 MHz. It uses PCIe 4.0 x16 and has 1x HDMI 2.1 and 3x DisplayPort 1.4a outputs. It is a Triple-slot card measuring 304 mm in length, 137 mm in height, and 61 mm in width. The TDP is 425 W with a 1x 16-pin power connector and an 800 W suggested PSU. It supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. The production status is end-of-life, with the GeForce 50 as its successor.

Where Each One Wins

The AMD Instinct MI455X wins decisively in memory capacity and bandwidth. With 432 GB of HBM4 and 23.3 TB/s of bandwidth, it offers 18 times the memory capacity and roughly 23 times the bandwidth of the RTX 4090 D. The compute throughput is also dramatically higher: the MI455X delivers 157.3 TFLOPS in both FP32 and FP16, which is more than double the RTX 4090 D's 73.54 TFLOPS in either precision. The texture rate of 2,457.6 GTexel/s is also more than double the 1,149.1 GTexel/s of the RTX 4090 D. The MI455X also has a wider memory bus at 24576 bits versus 384 bits, and a newer PCIe 6.0 interface compared to PCIe 4.0.

The NVIDIA GeForce RTX 4090 D wins in every graphics-specific metric. It has 176 ROPs and a pixel rate of 443.5 GPixel/s, while the MI455X has zero ROPs and a 0 MPixel/s pixel rate. The RTX 4090 D supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4, while the MI455X has no API support recorded. The RTX 4090 D has display outputs, making it usable as a graphics card, and it has RT cores and tensor cores that are entirely absent from the MI455X. The RTX 4090 D also has a higher base clock of 2280 MHz versus 1000 MHz, and a higher boost clock of 2520 MHz versus 2400 MHz. The transistor density of the RTX 4090 D is higher at 125.3M per mm² versus 107.0M per mm², despite the MI455X having a larger absolute transistor count.

FAQ

Q: Which card has more memory?

A: The AMD Instinct MI455X has 432 GB of HBM4, while the NVIDIA GeForce RTX 4090 D has 24 GB of GDDR6X.

Q: Which card has higher FP32 compute performance?

A: The AMD Instinct MI455X delivers 157.3 TFLOPS, more than double the 73.54 TFLOPS of the NVIDIA GeForce RTX 4090 D.

Q: Can the AMD Instinct MI455X output video to a display?

A: No, the MI455X has no display outputs, while the RTX 4090 D has 1x HDMI 2.1 and 3x DisplayPort 1.4a.

Q: What is the benchmark percentile ranking of each card?

A: The AMD Instinct MI455X is at the 50th percentile across all GPUs, while the NVIDIA GeForce RTX 4090 D is at the 98th percentile.

Q: Which card supports ray tracing?

A: The NVIDIA GeForce RTX 4090 D has 114 RT cores and supports DirectX 12 Ultimate, while the MI455X has no RT cores and no API support recorded.

Q: What is the power requirement difference?

A: The MI455X has a TDP of 2300 W and a suggested PSU of 2700 W, while the RTX 4090 D has a TDP of 425 W and a suggested PSU of 800 W.

Head-to-Head Benchmarks

The recorded benchmark data includes three tests for the NVIDIA GeForce RTX 4090 D, while the AMD Instinct MI455X has no benchmark scores in the database. The RTX 4090 D scores 8587 in 3dmark_3dmark_steel_nomad_dx12, 278621 in geekbench_opencl, and 246941 in geekbench_vulkan. The average benchmark score for the RTX 4090 D is 178050. The nearest rivals for the RTX 4090 D are the NVIDIA RTX PRO 5000 Blackwell with an average score of 182109 and a delta of -2.2%, the NVIDIA A100 SXM4 80 GB with 183725 and -3.1%, the NVIDIA RTX 5000 Ada Generation with 184664 and -3.6%, and the NVIDIA A100 SXM4 40 GB with 187147 and -4.9%. These deltas show the RTX 4090 D trails the nearest competitors by 2.2% to 4.9% in average benchmark score.

The absence of any benchmark entries for the MI455X means the database cannot directly compare the two in standardized tests. However, the raw specification data offers a clear picture. In FP32 throughput, the MI455X delivers 157.3 TFLOPS, which is 2.14 times the 73.54 TFLOPS of the RTX 4090 D. In FP16, the same ratio holds at 157.3 versus 73.54 TFLOPS. The memory bandwidth gap is even wider: 23.3 TB/s versus 1.01 TB/s, a factor of approximately 23. The texture rate difference is 2,457.6 GTexel/s versus 1,149.1 GTexel/s, meaning the MI455X processes textures more than twice as fast.

The RTX 4090 D counters with a pixel rate of 443.5 GPixel/s, which is an infinite multiple over the MI455X's 0 MPixel/s because the MI455X has no ROPs. The RTX 4090 D also has 176 ROPs versus zero for the MI455X, and it has 114 RT cores and 456 tensor cores where the MI455X has none recorded. The RTX 4090 D supports the latest graphics APIs, while the MI455X has none. The clock speeds also favor the RTX 4090 D: base clocks are 2280 MHz versus 1000 MHz, and boost clocks are 2520 MHz versus 2400 MHz.

In terms of physical characteristics, the MI455X has a die size of 2990 mm² compared to 609 mm² for the RTX 4090 D, and a transistor count of 320,000 million versus 76,300 million. The MI455X uses a 2 nm process, while the RTX 4090 D uses 5 nm. The MI455X's transistor density is lower at 107.0M per mm² versus 125.3M per mm², indicating the larger chip is not as densely packed.

The power envelope differs substantially. The MI455X has a TDP of 2300 W and requires a 2700 W suggested PSU, while the RTX 4090 D has a TDP of 425 W and an 800 W suggested PSU. The MI455X uses no power connectors, suggesting a direct board connection in a module form factor, while the RTX 4090 D uses a single 16-pin connector. The MI455X is an EAM Module, while the RTX 4090 D is a Triple-slot card with dimensions of 304 mm by 137 mm by 61 mm.

The release timeline also differs: the RTX 4090 D launched on 2023-12-27 and is already end-of-life, while the MI455X is scheduled for release on 2026-07-22. The RTX 4090 D has a launch MSRP of 1,599 USD. The MI455X has no recorded launch MSRP. The RTX 4090 D's predecessor is the GeForce 30 series and its successor is the GeForce 50 series, while the MI455X's predecessor is the Radeon Instinct line.

The data indicates the MI455X is a pure compute accelerator with no graphics capabilities, while the RTX 4090 D is a fully featured graphics card. The benchmark percentile of 98 for the RTX 4090 D reflects its strong performance in standardized graphics tests, while the MI455X's 50th percentile with zero benchmark entries suggests it is not intended for the same workload class. The MI455X's massive memory pool and bandwidth make it suitable for large-scale data processing, while the RTX 4090 D's display outputs, RT cores, and API support make it suitable for interactive graphics and gaming.