AMD Instinct MI355X vs NVIDIA GeForce RTX 4080 Mobile Comparison

Head-to-Head Benchmarks

The database contains no direct head-to-head benchmark results between the AMD Instinct MI355X and the NVIDIA GeForce RTX 4080 Mobile. The MI355X has no recorded benchmark entries, while the RTX 4080 Mobile has nine recorded scores across standard tests. This makes a direct numerical comparison impossible from the recorded data alone.

The RTX 4080 Mobile's recorded scores show a strong general-purpose profile. Its Geekbench OpenCL score of 159,575 and Geekbench Vulkan score of 145,807 indicate solid compute throughput in cross-platform workloads. Passmark results show a G3D score of 24,926, a GPU Compute score of 11,191, and legacy DirectX scores of 286 for DX9, 244 for DX11, 157 for DX10, and 96 for DX12. The G2D score of 929 reflects 2D graphics performance.

The MI355X, by contrast, has an average benchmark score of zero and sits at the 50th percentile among all GPUs in the database. The RTX 4080 Mobile reaches the 81st percentile with an average benchmark score of 38,135. The MI355X's nearest rivals list is empty, meaning no comparable benchmark data exists for it. The RTX 4080 Mobile's nearest rivals show it trading blows with similar-tier hardware: it sits 0.4% behind the NVIDIA GeForce MX570, 0.6% behind the RTX 5080 Mobile, and 1.3% ahead of both the RTX 4070 and the Tesla P4.

The absence of MI355X benchmark data is itself informative. It indicates the part has not been tested in the database's standard suite, likely due to its purpose as an accelerator without display outputs rather than a general-purpose graphics card. The RTX 4080 Mobile's scores, however, provide a reference point for what mainstream mobile GPUs achieve in these tests.

FAQ

Q: Does the AMD Instinct MI355X have any benchmark scores in the database?

A: No. The MI355X has an empty benchmark list, an average benchmark score of 0, and no nearest rivals. Its percentile rank is 50, meaning it sits at the median of all GPUs in the database, but this is based on no recorded test results.

Q: What is the RTX 4080 Mobile's best recorded benchmark score?

A: Its highest single score is 159,575 on Geekbench OpenCL, followed by 145,807 on Geekbench Vulkan. Among Passmark tests, the G3D score of 24,926 is the strongest.

Q: How does the RTX 4080 Mobile compare to its nearest rivals?

A: The recorded data shows it is 0.4% slower than the MX570, 0.6% slower than the RTX 5080 Mobile, and 1.3% faster than both the RTX 4070 and the Tesla P4 in average benchmark score.

Q: Which GPU has higher FP32 throughput?

A: The MI355X delivers 78.64 TFLOPS, while the RTX 4080 Mobile delivers 24.72 TFLOPS. The MI355X has more than three times the FP32 compute.

Q: What is the memory configuration difference?

A: The MI355X uses 288 GB of HBM3e on an 8192-bit bus with 8.19 TB/s bandwidth. The RTX 4080 Mobile uses 12 GB of GDDR6 on a 192-bit bus with 432.0 GB/s bandwidth.

Q: Does the MI355X support DirectX or Vulkan?

A: No. Its API support is listed as N/A for DirectX, OpenGL, and Vulkan. The RTX 4080 Mobile supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4.

Architecture Differences

The two GPUs come from fundamentally different design philosophies. The MI355X uses AMD's CDNA 4.0 architecture, built for data center compute workloads. The RTX 4080 Mobile uses NVIDIA's Ada Lovelace architecture, designed for mobile gaming and professional graphics.

The MI355X is fabricated on a 3 nm process at TSMC, while the RTX 4080 Mobile uses a 5 nm process at the same foundry. The MI355X packs 185,000 million transistors on a 2380 mm² die, yielding a transistor density of 77.7 million per mm². The RTX 4080 Mobile has 35,800 million transistors on a 294 mm² die, with a density of 121.8 million per mm². The MI355X die is dramatically larger, but the RTX 4080 Mobile's smaller process node advantage in density is notable.

The MI355X uses the MI350 256CU chip, which indicates 256 compute units. It has 16,384 shading units, 1,024 texture mapping units, and zero ROPs. The RTX 4080 Mobile uses the AD104 chip with 7,424 shading units, 232 TMUs, and 80 ROPs. The MI355X has no dedicated ray tracing cores or tensor cores listed, while the RTX 4080 Mobile has 58 RT cores and 232 tensor cores.

The MI355X's pixel rate is listed as 0 MPixel/s, which reflects its lack of display outputs. Its texture rate is 2,457.6 GTexel/s, compared to the RTX 4080 Mobile's 386.3 GTexel/s. Both GPUs handle FP16 at a 1:1 ratio with FP32, meaning their FP16 throughput matches their FP32 figures.

The MI355X's API support is entirely absent, with no DirectX, OpenGL, or Vulkan capability. The RTX 4080 Mobile supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4. This reflects the MI355X's role as a compute accelerator rather than a graphics renderer. The MI355X also has no display outputs, while the RTX 4080 Mobile's outputs are portable device dependent.

Specification Differences

The clock speeds differ significantly. The MI355X has a base clock of 1000 MHz and a boost clock of 2400 MHz. The RTX 4080 Mobile has a base of 1290 MHz and a boost of 1665 MHz. The MI355X's memory runs at 2000 MHz with 8 Gbps effective, while the RTX 4080 Mobile's memory runs at 2250 MHz with 18 Gbps effective.

Memory capacity and bandwidth favor the MI355X overwhelmingly. It has 288 GB of HBM3e across an 8192-bit bus, delivering 8.19 TB/s. The RTX 4080 Mobile has 12 GB of GDDR6 across a 192-bit bus, delivering 432.0 GB/s. The MI355X offers 24 times the memory capacity and roughly 19 times the bandwidth.

Power and physical specifications show their different deployment contexts. The MI355X has a TDP of 1400 W, a suggested PSU of 1800 W, and uses an OAM Module slot width. It has no power connectors listed. The RTX 4080 Mobile has a TDP of 110 W, an IGP slot width, and no power connectors either. The MI355X measures 102 mm by 165 mm, while the RTX 4080 Mobile has no listed dimensions.

The bus interfaces differ: the MI355X uses PCIe 5.0 x16, while the RTX 4080 Mobile uses PCIe 4.0 x16. Release dates also differ, with the MI355X launching on June 11, 2025, and the RTX 4080 Mobile launching on January 2, 2023. The RTX 4080 Mobile's production status is Active, while the MI355X has no production status listed.

The MI355X's predecessor is listed as Radeon Instinct, while the RTX 4080 Mobile's predecessor is GeForce 30 Mobile and its successor is GeForce 50 Mobile. Neither part has a listed launch MSRP.

Where Each One Wins

The MI355X wins decisively in raw compute capability. Its FP32 throughput of 78.64 TFLOPS more than triples the RTX 4080 Mobile's 24.72 TFLOPS. Its texture rate of 2,457.6 GTexel/s is more than six times the RTX 4080 Mobile's 386.3 GTexel/s. The memory subsystem is the biggest differentiator: 288 GB with 8.19 TB/s bandwidth versus 12 GB with 432.0 GB/s. For workloads that fit in memory, the MI355X offers massive bandwidth advantages.

The RTX 4080 Mobile wins in graphics features and ecosystem compatibility. It supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4, making it usable in gaming and general graphics applications. The MI355X supports none of these APIs. The RTX 4080 Mobile also has 80 ROPs, enabling pixel output of 133.2 GPixel/s, while the MI355X has zero ROPs and no pixel rate. The RTX 4080 Mobile's ray tracing cores and tensor cores provide hardware acceleration for those workloads, which the MI355X lacks entirely.

The RTX 4080 Mobile also wins on efficiency in practical terms. Its 110 W TDP is a fraction of the MI355X's 1400 W. The RTX 4080 Mobile's smaller die, lower transistor count, and higher transistor density suggest a more compact implementation. Its benchmark presence, with nine recorded scores and the 81st percentile ranking, demonstrates tested real-world performance. The MI355X has no recorded scores to validate its theoretical specifications.

The RTX 4080 Mobile's nearest rival data shows it performs competitively within its class, sitting within 1.3% of similarly positioned GPUs. The MI355X has no rival data at all.

The Verdict

The data describes two GPUs with almost no overlap in purpose. The MI355X is a data center accelerator with enormous memory capacity, extreme bandwidth, and massive FP32 compute, but it lacks any graphics API support, display outputs, or rasterization hardware. Its 1400 W TDP and OAM Module form factor place it in server racks, not desktop systems. The absence of benchmark scores means its real-world performance in the database's tests is unmeasured.

The RTX 4080 Mobile is a mobile graphics processor with conventional GPU features: ROPs, ray tracing cores, tensor cores, full API support, and display outputs. Its 110 W TDP suits laptop integration. Its benchmark scores are recorded and place it at the 81st percentile among all GPUs, with competitive results against its nearest rivals.

For compute-heavy workloads that require massive memory capacity and bandwidth, the MI355X's specifications make it the clear choice based on paper metrics alone. For any task involving graphics rendering, gaming, or standard GPU APIs, the RTX 4080 Mobile is the only viable option between the two, as the MI355X cannot render frames or output video at all.

The RTX 4080 Mobile's benchmark results confirm it performs well in general-purpose GPU tasks, while the MI355X remains an unverified specification sheet. Users needing a tested, functional GPU should select the RTX 4080 Mobile. Users with data center workloads that fit within the MI355X's capabilities must rely on its theoretical specifications, as the database contains no performance validation for it.