AMD Instinct MI455X vs NVIDIA GeForce RTX 4080 SUPER Comparison

FAQ

Q: What is the architectural foundation of the AMD Instinct MI455X?

A: The AMD Instinct MI455X is built on the CDNA 5.0 architecture, using the MI450 256CU chip, and is manufactured on a 2 nm process at TSMC. It belongs to the Instinct (MIx) generation.

Q: What memory configuration does the NVIDIA GeForce RTX 4080 SUPER use?

A: The RTX 4080 SUPER uses 16 GB of GDDR6X memory on a 256-bit bus, with a bandwidth of 736.3 GB/s. Its memory clock runs at 1438 MHz, which translates to 23 Gbps effective.

Q: Which GPU has a higher transistor density?

A: The NVIDIA GeForce RTX 4080 SUPER has a transistor density of 121.1M per mm², while the AMD Instinct MI455X has a density of 107.0M per mm². The RTX 4080 SUPER packs more transistors per square millimeter despite having fewer total transistors.

Q: What is the pixel rate of the AMD Instinct MI455X?

A: The AMD Instinct MI455X has a pixel rate of 0 MPixel/s. This is because it has 0 ROPs, meaning it is not designed for traditional rasterized display output.

Q: What is the average benchmark score for the NVIDIA GeForce RTX 4080 SUPER?

A: The RTX 4080 SUPER has an average benchmark score of 54209 and sits in the 86th percentile among all GPUs in the database. Its closest rival, the NVIDIA GeForce RTX 4080, scores 54247, which is a delta of -0.1%.

Q: Does the AMD Instinct MI455X have any benchmark scores recorded?

A: No, the database lists no benchmark scores for the AMD Instinct MI455X. Its average benchmark score is 0, and it holds a 50th percentile ranking, with no nearest rivals listed.

Architecture Differences

The AMD Instinct MI455X and NVIDIA GeForce RTX 4080 SUPER represent fundamentally different design philosophies. The MI455X uses AMD's CDNA 5.0 architecture, a compute-optimized design aimed at acceleration workloads. The RTX 4080 SUPER uses NVIDIA's Ada Lovelace architecture, which is a consumer graphics architecture with full rasterization and ray tracing support.

The process nodes differ significantly. The MI455X is fabricated on a 2 nm process at TSMC, while the RTX 4080 SUPER uses a 5 nm process, also at TSMC. The MI455X contains 320,000 million transistors on a die size of 2990 mm², resulting in a density of 107.0M per mm². The RTX 4080 SUPER contains 45,900 million transistors on a 379 mm² die, yielding a higher density of 121.1M per mm².

Memory architecture is another major divergence. The MI455X uses HBM4 memory with a staggering 432 GB capacity and a 24576-bit bus width, delivering 23.3 TB/s of bandwidth. The RTX 4080 SUPER uses GDDR6X with 16 GB capacity on a 256-bit bus, providing 736.3 GB/s. The MI455X's memory bandwidth is over 30 times higher, reflecting its purpose for data-intensive workloads.

The compute resources differ sharply. The MI455X has 32768 shading units, 1024 TMUs, and 0 ROPs. The RTX 4080 SUPER has 10240 shading units, 320 TMUs, and 112 ROPs. The MI455X's lack of ROPs indicates it is not built for outputting pixels to a display. The RTX 4080 SUPER includes 80 RT cores and 320 tensor cores, while the MI455X lists no RT or tensor core counts.

Texture and pixel rates confirm the divergence. The MI455X delivers a texture rate of 2,457.6 GTexel/s but 0 MPixel/s. The RTX 4080 SUPER produces 816.0 GTexel/s and 285.6 GPixel/s. FP32 performance shows the MI455X at 157.3 TFLOPS, while the RTX 4080 SUPER reaches 52.22 TFLOPS. Both GPUs have a 1:1 FP16 to FP32 ratio.

Power and physical design also differ. The MI455X has a TDP of 2300 W and uses no power connectors, with a suggested PSU of 2700 W. It is an EAM Module form factor. The RTX 4080 SUPER has a TDP of 320 W, uses a single 16-pin connector, has a suggested PSU of 700 W, and is a triple-slot card measuring 310 mm by 140 mm by 61 mm.

The bus interfaces differ as well. The MI455X uses PCIe 6.0 x16, while the RTX 4080 SUPER uses PCIe 4.0 x16. The MI455X has no display outputs and no API support for DirectX, OpenGL, or Vulkan. The RTX 4080 SUPER supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4, with outputs including 1x HDMI 2.1 and 3x DisplayPort 1.4a.

The Verdict

The data indicates these two GPUs serve entirely different purposes. The AMD Instinct MI455X is a compute accelerator with no display outputs, no rasterization hardware, and no consumer API support. Its 432 GB of HBM4 memory, 23.3 TB/s bandwidth, and 157.3 TFLOPS FP32 performance place it firmly in the data center and high-performance computing segment. Its 2300 W TDP and EAM Module form factor confirm it is not intended for desktop use.

The NVIDIA GeForce RTX 4080 SUPER is a consumer graphics card. It has full display outputs, DirectX 12 Ultimate support, 80 RT cores for ray tracing, and 320 tensor cores for AI acceleration. Its 16 GB of GDDR6X memory and 736.3 GB/s bandwidth are ample for gaming and workstation tasks. The recorded benchmark scores show it performs strongly: a 3DMark Steel Nomad DX12 score of 6600, GeekBench OpenCL score of 219065, GeekBench Vulkan score of 260075, and PassMark G3D score of 34245. Its average benchmark score of 54209 places it in the 86th percentile of all GPUs.

For users requiring a GPU for rendering, gaming, or general desktop workloads, the RTX 4080 SUPER is the only viable option, given the MI455X's lack of display outputs and consumer software support. For users running massive compute workloads that need enormous memory capacity and bandwidth, the MI455X's specifications are unmatched by the RTX 4080 SUPER. The choice depends entirely on the workload: consumer graphics versus data center compute.

Specification Differences

The two GPUs differ in nearly every major specification category. The process node differs: the MI455X uses 2 nm, the RTX 4080 SUPER uses 5 nm. Transistor counts are 320,000 million versus 45,900 million. Die size is 2990 mm² versus 379 mm². Transistor density favors the RTX 4080 SUPER at 121.1M per mm² versus 107.0M per mm².

Clock speeds differ substantially. The MI455X has a base clock of 1000 MHz and a boost clock of 2400 MHz. The RTX 4080 SUPER has a base clock of 2295 MHz and a boost clock of 2550 MHz. Memory clocks are 1900 MHz (7.6 Gbps effective) for the MI455X and 1438 MHz (23 Gbps effective) for the RTX 4080 SUPER.

Memory capacity, type, bus width, and bandwidth all differ. The MI455X offers 432 GB of HBM4 on a 24576-bit bus with 23.3 TB/s. The RTX 4080 SUPER offers 16 GB of GDDR6X on a 256-bit bus with 736.3 GB/s.

Compute resources differ: 32768 shading units, 1024 TMUs, and 0 ROPs on the MI455X; 10240 shading units, 320 TMUs, and 112 ROPs on the RTX 4080 SUPER. The RTX 4080 SUPER has 80 RT cores and 320 tensor cores; the MI455X has none listed.

Pixel rate is 0 MPixel/s for the MI455X versus 285.6 GPixel/s for the RTX 4080 SUPER. Texture rate is 2,457.6 GTexel/s versus 816.0 GTexel/s. FP32 is 157.3 TFLOPS versus 52.22 TFLOPS. FP16 is also 157.3 TFLOPS versus 52.22 TFLOPS.

Power requirements differ drastically: 2300 W TDP with no power connectors and a 2700 W suggested PSU for the MI455X; 320 W TDP with a 1x 16-pin connector and a 700 W suggested PSU for the RTX 4080 SUPER. The form factors are EAM Module versus triple-slot. The bus interface is PCIe 6.0 x16 versus PCIe 4.0 x16.

Display outputs: none on the MI455X; 1x HDMI 2.1 and 3x DisplayPort 1.4a on the RTX 4080 SUPER. API support: none on the MI455X; DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4 on the RTX 4080 SUPER. Release dates are 2026-07-22 for the MI455X and 2024-01-30 for the RTX 4080 SUPER. The RTX 4080 SUPER has a launch MSRP of 999 USD. The MI455X has no launch MSRP listed.

Head-to-Head Benchmarks

The head-to-head benchmark section contains no recorded comparison data. The database lists zero head-to-head benchmarks between the AMD Instinct MI455X and the NVIDIA GeForce RTX 4080 SUPER, with winsA and winsB both at 0.

The RTX 4080 SUPER does have its own benchmark scores. Its 3DMark Steel Nomad DX12 score is 6600. GeekBench OpenCL yields 219065, and GeekBench Vulkan yields 260075. PassMark scores include 193 for DirectX 10, 301 for DirectX 11, 134 for DirectX 12, 381 for DirectX 9, 1270 for G2D, 34245 for G3D, and 19822 for GPU Compute. The average benchmark score is 54209, placing it in the 86th percentile.

The MI455X has no benchmark scores in the database. Its average benchmark score is 0, and its percentile ranking is 50. This means no direct comparison can be made from measured performance data.

The RTX 4080 SUPER's nearest rivals provide context for its measured performance. The NVIDIA GeForce RTX 4080 has an average score of 54247, a delta of -0.1% relative to the RTX 4080 SUPER. The AMD Radeon Pro W5700X scores 54828, a delta of -1.1%. The AMD Radeon RX 6750 GRE 12 GB scores 55698, a delta of -2.7%. The AMD Radeon 8060S scores 55757, a delta of -2.8%.

These deltas indicate the RTX 4080 SUPER trails its nearest rivals by small margins, between 0.1% and 2.8%. The performance difference between the RTX 4080 SUPER and its closest competitor, the RTX 4080, is negligible at 0.1%. The gap widens slightly with the Radeon Pro W5700X at 1.1%, then to 2.7% and 2.8% for the RX 6750 GRE and Radeon 8060S respectively.

Given the absence of head-to-head data, the only conclusion supported by the database is that the RTX 4080 SUPER has measured performance in the 86th percentile, while the MI455X has no recorded measurements. The MI455X's raw specifications suggest high compute capability, but no benchmark data confirms this. The RTX 4080 SUPER's performance is verified across multiple test suites, including 3DMark, GeekBench, and PassMark.