AMD Instinct MI455X vs NVIDIA GeForce RTX 4080 Mobile Comparison

Head-to-Head Benchmarks

The recorded data for the AMD Instinct MI455X contains no benchmark scores, while the NVIDIA GeForce RTX 4080 Mobile has a full set of nine benchmark results. Direct head-to-head comparisons are therefore not possible from the database. The MI455X has an average benchmark score of 0 and a percentile ranking of 50 among all GPUs, while the RTX 4080 Mobile averages 38,135 points and sits in the 81st percentile. The RTX 4080 Mobile delivers a Geekbench OpenCL score of 159,575 and a Geekbench Vulkan score of 145,807. In Passmark tests, the RTX 4080 Mobile shows 24,926 in G3D, 11,191 in GPU compute, 929 in G2D, 286 in DirectX 9, 244 in DirectX 11, 157 in DirectX 10, and 96 in DirectX 12.

The RTX 4080 Mobile’s nearest rivals in the database include the NVIDIA GeForce MX570 with an average score of 38,299, a delta of -0.4 percent, the NVIDIA GeForce RTX 5080 Mobile at 38,349 with a delta of -0.6 percent, the NVIDIA GeForce RTX 4070 at 37,648 with a delta of 1.3 percent, and the NVIDIA Tesla P4 at 37,628 with a delta of 1.3 percent. The RTX 4080 Mobile trails the MX570 and RTX 5080 Mobile by small margins, but it edges out the RTX 4070 and Tesla P4 by 1.3 percent each. These delta values indicate that the RTX 4080 Mobile performs within a narrow band around its closest competitors, with no dominant lead or deficit in the aggregate score.

For the MI455X, the absence of benchmark data means its percentile rank of 50 is a neutral placement, not a measured performance level. The database records no wins for either part in head-to-head testing, as the winsA and winsB fields are both zero. The MI455X’s average benchmark score of zero reflects no recorded submissions rather than a literal performance result. The RTX 4080 Mobile, by contrast, has measurable scores across DirectX 9 through 12, OpenCL, Vulkan, and general-purpose compute workloads. Its strongest relative result appears in Geekbench OpenCL, where the score of 159,575 exceeds its Vulkan score of 145,807 by about 9.4 percent.

Architecture Differences

The MI455X uses the MI450 256CU chip built on CDNA 5.0 architecture, fabricated on a 2 nm process at TSMC. The RTX 4080 Mobile uses the AD104 chip with Ada Lovelace architecture on a 5 nm process, also from TSMC. The MI455X contains 320,000 million transistors on a die size of 2990 mm², giving a transistor density of 107.0 million per mm². The RTX 4080 Mobile has 35,800 million transistors on a 294 mm² die, with a higher density of 121.8 million per mm². The MI455X is a massive compute-oriented accelerator, while the RTX 4080 Mobile is a compact mobile graphics processor.

Memory configurations differ sharply. The MI455X has 432 GB of HBM4 memory on a 24576-bit bus, delivering 23.3 TB/s of bandwidth. The RTX 4080 Mobile has 12 GB of GDDR6 memory on a 192-bit bus, with 432.0 GB/s of bandwidth. The MI455X’s memory bandwidth is roughly 54 times higher than the RTX 4080 Mobile’s, based on the recorded figures. Clock speeds also diverge: the MI455X runs at a 1000 MHz base and 2400 MHz boost, while the RTX 4080 Mobile runs at 1290 MHz base and 1665 MHz boost. The MI455X has a higher boost clock by 735 MHz, but the RTX 4080 Mobile has a higher base clock by 290 MHz.

Compute resources differ by an order of magnitude. The MI455X has 32,768 shading units, 1,024 texture mapping units, and no ROPs, with a pixel rate of 0 MPixel/s and a texture rate of 2,457.6 GTexel/s. The RTX 4080 Mobile has 7,424 shading units, 232 TMUs, and 80 ROPs, with a pixel rate of 133.2 GPixel/s and a texture rate of 386.3 GTexel/s. The MI455X delivers 157.3 TFLOPS in both FP32 and FP16, while the RTX 4080 Mobile delivers 24.72 TFLOPS in both precisions. The MI455X provides roughly 6.4 times the FP32 throughput of the RTX 4080 Mobile.

Feature sets also differ. The RTX 4080 Mobile includes 58 ray tracing cores and 232 tensor cores, while the MI455X records no RT or tensor core counts. The RTX 4080 Mobile supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4, while the MI455X lists N/A for all three APIs. The MI455X has no display outputs, while the RTX 4080 Mobile has portable-device-dependent outputs. The MI455X uses a PCIe 6.0 x16 interface, while the RTX 4080 Mobile uses PCIe 4.0 x16. Power requirements differ substantially, with the MI455X rated at 2300 W TDP and a suggested PSU of 2700 W, compared to the RTX 4080 Mobile’s 110 W TDP.

Where Each One Wins

The MI455X wins decisively in raw compute throughput. Its FP32 score of 157.3 TFLOPS is 6.4 times the RTX 4080 Mobile’s 24.72 TFLOPS. Its texture rate of 2,457.6 GTexel/s is roughly 6.4 times the RTX 4080 Mobile’s 386.3 GTexel/s. Memory capacity and bandwidth strongly favor the MI455X: 432 GB versus 12 GB, and 23.3 TB/s versus 432.0 GB/s. The MI455X also has a wider memory bus at 24576 bits versus 192 bits, and it uses HBM4 rather than GDDR6. For workloads that depend on massive memory pools or extreme bandwidth, such as large-scale data processing or high-resolution compute tasks, the MI455X’s recorded specifications place it far ahead.

The RTX 4080 Mobile wins in graphics-oriented features and measurable benchmark results. It has 80 ROPs and a pixel rate of 133.2 GPixel/s, while the MI455X has zero ROPs and zero pixel rate. The RTX 4080 Mobile includes 58 ray tracing cores and 232 tensor cores, which the MI455X lacks entirely. The RTX 4080 Mobile supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4, while the MI455X supports none of these APIs. The RTX 4080 Mobile also has a higher transistor density at 121.8 million per mm² versus 107.0 million per mm², indicating more efficient packing on a smaller die. The RTX 4080 Mobile’s lower base clock advantage of 1290 MHz versus 1000 MHz helps in latency-sensitive tasks.

In terms of power efficiency, the RTX 4080 Mobile delivers 24.72 TFLOPS at 110 W, while the MI455X delivers 157.3 TFLOPS at 2300 W. Per watt, the RTX 4080 Mobile produces about 0.225 TFLOPS per watt, while the MI455X produces about 0.068 TFLOPS per watt, based on the recorded figures. The RTX 4080 Mobile is therefore more efficient in floating-point operations per watt, though the MI455X still offers far higher absolute throughput. The RTX 4080 Mobile’s production status is listed as active, while the MI455X has no production status recorded. The RTX 4080 Mobile also has a successor, the GeForce 50 Mobile, whereas the MI455X has no successor listed.

The Verdict

The data indicates two fundamentally different products. The AMD Instinct MI455X is a compute accelerator with no display outputs, no graphics API support, and no recorded benchmarks. Its strengths lie in sheer scale: 32,768 shading units, 432 GB of HBM4 memory, 23.3 TB/s bandwidth, and 157.3 TFLOPS of FP32 performance. The RTX 4080 Mobile is a mobile graphics processor with active production status, a full API set, and nine recorded benchmark scores. Its strengths lie in graphics rendering, ray tracing, tensor operations, and measurable real-world results across DirectX, OpenGL, Vulkan, OpenCL, and compute workloads.

For a user whose workload is massive parallel compute with enormous memory requirements, the MI455X’s specifications point to it as the appropriate choice. For a user needing graphics output, API compatibility, ray tracing, or portable deployment, the RTX 4080 Mobile is the only viable option, since the MI455X offers no display outputs and no graphics APIs. The RTX 4080 Mobile’s benchmark scores, including 159,575 in OpenCL and 145,807 in Vulkan, confirm it functions in real workloads, while the MI455X has no such evidence in the database.

The RTX 4080 Mobile also has a clear competitive context, sitting within 1.3 percent of the MX570, RTX 5080 Mobile, RTX 4070, and Tesla P4 in average score. The MI455X has no nearest rivals listed, reinforcing its isolated position in the database. The MI455X’s 50th percentile placement versus the RTX 4080 Mobile’s 81st percentile is not directly comparable, as the MI455X’s percentile is based on zero benchmark data. Selection should follow the workload: compute density for the MI455X, graphics and portability for the RTX 4080 Mobile.

FAQ

Q: What is the FP32 performance difference between the two?

A: The AMD Instinct MI455X delivers 157.3 TFLOPS in FP32, while the NVIDIA GeForce RTX 4080 Mobile delivers 24.72 TFLOPS. The MI455X is approximately 6.4 times faster in raw FP32 throughput.

Q: How much memory and bandwidth does each GPU have?

A: The MI455X has 432 GB of HBM4 memory with 23.3 TB/s bandwidth on a 24576-bit bus. The RTX 4080 Mobile has 12 GB of GDDR6 memory with 432.0 GB/s bandwidth on a 192-bit bus.

Q: Which GPU supports ray tracing and tensor cores?

A: The NVIDIA GeForce RTX 4080 Mobile includes 58 ray tracing cores and 232 tensor cores. The AMD Instinct MI455X records no RT or tensor core counts in the database.

Q: What are the power requirements for each?

A: The MI455X has a TDP of 2300 W with a suggested PSU of 2700 W. The RTX 4080 Mobile has a TDP of 110 W and no suggested PSU listed.

Q: Does the MI455X have any benchmark scores?

A: No. The MI455X has an empty benchmark list, an average score of 0, and no nearest rivals. The RTX 4080 Mobile has nine recorded benchmark scores, including a Geekbench OpenCL score of 159,575 and a Passmark G3D score of 24,926.

Q: What are the process nodes and die sizes?

A: The MI455X is built on a 2 nm process with a die size of 2990 mm², containing 320,000 million transistors. The RTX 4080 Mobile is built on a 5 nm process with a die size of 294 mm², containing 35,800 million transistors.

Specification Differences

| Specification | AMD Instinct MI455X | NVIDIA GeForce RTX 4080 Mobile |

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

| Architecture | CDNA 5.0 | Ada Lovelace |

| Process Node | 2 nm | 5 nm |

| Transistors | 320,000 million | 35,800 million |

| Die Size | 2990 mm² | 294 mm² |

| Transistor Density | 107.0M / mm² | 121.8M / mm² |

| Base Clock | 1000 MHz | 1290 MHz |

| Boost Clock | 2400 MHz | 1665 MHz |

| Memory Size | 432 GB | 12 GB |

| Memory Type | HBM4 | GDDR6 |

| Memory Bus Width | 24576 bit | 192 bit |

| Memory Bandwidth | 23.3 TB/s | 432.0 GB/s |

| Shading Units | 32768 | 7424 |

| TMUs | 1024 | 232 |

| ROPs | 0 | 80 |

| RT Cores | None | 58 |

| Tensor Cores | None | 232 |

| Pixel Rate | 0 MPixel/s | 133.2 GPixel/s |

| Texture Rate | 2,457.6 GTexel/s | 386.3 GTexel/s |

| FP32 | 157.3 TFLOPS | 24.72 TFLOPS |

| FP16 | 157.3 TFLOPS (1:1) | 24.72 TFLOPS (1:1) |

| TDP | 2300 W | 110 W |

| Suggested PSU | 2700 W | None |

| Bus Interface | PCIe 6.0 x16 | PCIe 4.0 x16 |

| Display Outputs | No outputs | Portable Device Dependent |

| DirectX | N/A | 12 Ultimate (12_2) |

| OpenGL | N/A | 4.6 |

| Vulkan | N/A | 1.4 |

| Production Status | None | Active |

| Release Date | 2026-07-22 | 2023-01-02 |

| Predecessor | Radeon Instinct | GeForce 30 Mobile |

| Successor | None | GeForce 50 Mobile |