AMD Instinct MI455X vs NVIDIA N1 20SM Comparison

Head-to-Head Benchmarks

The recorded database contains no direct benchmark results for either the AMD Instinct MI455X or the NVIDIA N1 20SM. Both entries show an average benchmark score of zero, and the head-to-head comparison list is empty. The percentile versus all GPUs is identical for both parts at 50, which indicates neither has been measured against the full database population. Without measured scores, the data cannot establish a performance hierarchy through direct comparison.

The absence of benchmark data does not obscure the raw specification differences. The AMD Instinct MI455X delivers 157.3 TFLOPS of FP32 compute, while the NVIDIA N1 20SM delivers 12.01 TFLOPS. That is a 13.1x gap in raw floating-point throughput. The MI455X also reaches 157.3 TFLOPS for FP16 with a 1:1 ratio, whereas the N1 20SM provides 12.01 TFLOPS FP16, also at 1:1. Texture rate follows the same pattern: 2,457.6 GTexel/s for the AMD part versus 375.4 GTexel/s for the NVIDIA part.

Memory bandwidth shows the largest absolute difference. The MI455X has 23.3 TB/s of bandwidth from its HBM4 stack, while the N1 20SM has 273.2 GB/s from LPDDR5X. Converting to consistent units, 23,300 GB/s versus 273.2 GB/s means the AMD part has approximately 85.3x more memory bandwidth. The memory capacity difference is 432 GB versus 128 GB, a 3.4x gap.

Pixel rate is the one metric where the NVIDIA part produces a nonzero result. The N1 20SM has a pixel rate of 56.30 GPixel/s, while the MI455X shows 0 MPixel/s. This reflects the AMD part having zero ROPs, as the MI455X lists 0 ROPs and 0 pixel rate. The N1 20SM has 24 ROPs. For rendering-oriented workloads that rely on pixel output, the data indicates the NVIDIA part has functionality the AMD part lacks entirely.

Clock behavior also differs. The MI455X has a base clock of 1000 MHz and a boost of 2400 MHz, a 2.4x boost ratio. The N1 20SM has a base of 741 MHz and a boost of 2346 MHz, a 3.2x boost ratio. The NVIDIA part relies on a wider relative boost range, while the AMD part starts from a higher base and reaches a higher absolute boost frequency.

Where Each One Wins

The AMD Instinct MI455X wins in every compute-oriented metric recorded. FP32 throughput, FP16 throughput, texture rate, memory bandwidth, memory capacity, and shading unit count all favor the AMD part. The MI455X has 32,768 shading units versus 2,560 for the N1 20SM, a 12.8x difference. TMUs number 1,024 versus 160, a 6.4x difference. These specification gaps point to workloads that scale with parallel shader execution and texture fetch throughput.

The NVIDIA N1 20SM wins in pixel output and integration efficiency. With 24 ROPs and a 56.30 GPixel/s pixel rate, the N1 20SM can perform rasterization work that the MI455X cannot, since the AMD part lists zero ROPs and zero pixel rate. The N1 20SM also has dedicated ray tracing cores, 20 of them, and tensor cores, 80 of them, while the MI455X lists null for both categories. The NVIDIA part includes a display output, one HDMI port, while the MI455X has no display outputs.

The N1 20SM uses a smaller die, 382 mm², compared to 2990 mm² for the MI455X. The process node differs as well: the MI455X uses a 2 nm process from TSMC, while the N1 20SM uses a 5 nm process from the same foundry. The AMD part has 320,000 million transistors, while the transistor count for the NVIDIA part is listed as unknown. Transistor density for the MI455X is 107.0M per mm²; no density figure exists for the N1 20SM.

The memory type separates the two parts into distinct usage classes. HBM4 with a 24576-bit bus width positions the MI455X for massive data movement, while LPDDR5X with a 256-bit bus width positions the N1 20SM for integrated, power-constrained operation. The N1 20SM is classified as an IGP (integrated graphics processor) with a slot width of "IGP", whereas the MI455X uses an EAM module form factor.

Architecture Differences

The AMD Instinct MI455X uses the CDNA 5.0 architecture, built on the MI450 256CU chip. The NVIDIA N1 20SM uses the Blackwell 2.0 architecture, built on the GB20B chip. These are different architectural families from different vendors, with different design goals reflected in their configuration.

The MI455X has no ray tracing cores listed and no tensor cores listed. The N1 20SM has 20 ray tracing cores and 80 tensor cores. The AMD part compensates with raw shader throughput: 32,768 shading units, 1,024 TMUs, and 157.3 TFLOPS FP32. The NVIDIA part has 2,560 shading units, 160 TMUs, and 12.01 TFLOPS FP32. The AMD architecture appears optimized for dense compute, while the NVIDIA architecture includes specialized acceleration blocks.

Memory architecture diverges sharply. The MI455X uses HBM4 with a 24576-bit bus and 23.3 TB/s bandwidth, running at 1900 MHz with 7.6 Gbps effective. The N1 20SM uses LPDDR5X with a 256-bit bus and 273.2 GB/s bandwidth, running at 1067 MHz with 8.5 Gbps effective. The AMD part has 432 GB of memory, the NVIDIA part has 128 GB. The AMD memory controller is 96 times wider in bus width terms.

Process technology differences are significant. The MI455X uses a 2 nm node from TSMC, while the N1 20SM uses a 5 nm node from the same foundry. The AMD die measures 2990 mm², the NVIDIA die measures 382 mm². The MI455X packs 320,000 million transistors, achieving 107.0M per mm² density. The N1 20SM transistor count is unknown.

Power and connectivity also separate the parts. The MI455X has a TDP of 2300 W and a suggested PSU of 2700 W. The N1 20SM has an unknown TDP and no suggested PSU listed. Both use PCIe, but the MI455X uses PCIe 6.0 x16 while the N1 20SM uses PCIe 5.0 x16. The MI455X has no power connectors listed, and neither part has external power connectors in the data.

The release dates show the N1 20SM entered production first. The NVIDIA part has a release date of 2026-05-31 and an active production status. The AMD part has a release date of 2026-07-22, roughly two months later. The MI455X has no production status listed. The predecessor for the AMD part is Radeon Instinct, while the NVIDIA part has no predecessor listed.

API support is identical in the data: both parts list DirectX as N/A, OpenGL as N/A, and Vulkan as N/A. Neither part exposes standard graphics APIs, which aligns with the MI455X having no display outputs and the N1 20SM having a single HDMI output despite its IGP classification.

FAQ

Q: Which GPU has higher FP32 compute performance?

A: The AMD Instinct MI455X delivers 157.3 TFLOPS FP32, while the NVIDIA N1 20SM delivers 12.01 TFLOPS FP32. The AMD part provides 13.1x more FP32 throughput.

Q: How do the memory subsystems compare?

A: The MI455X has 432 GB of HBM4 memory with a 24576-bit bus and 23.3 TB/s bandwidth. The N1 20SM has 128 GB of LPDDR5X memory with a 256-bit bus and 273.2 GB/s bandwidth. The AMD part has 3.4x more capacity and approximately 85.3x more bandwidth.

Q: Does either GPU support ray tracing or tensor operations?

A: The NVIDIA N1 20SM includes 20 ray tracing cores and 80 tensor cores. The AMD Instinct MI455X lists null for both ray tracing cores and tensor cores, indicating no dedicated hardware for those functions in the recorded data.

Q: What are the physical differences between the two parts?

A: The MI455X uses a 2990 mm² die on a 2 nm TSMC process, while the N1 20SM uses a 382 mm² die on a 5 nm TSMC process. The MI455X has 320,000 million transistors with a density of 107.0M per mm². The N1 20SM transistor count is unknown.

Q: Which part has display output capability?

A: The NVIDIA N1 20SM has one HDMI output. The AMD Instinct MI455X has no display outputs, consistent with its zero ROP count and zero pixel rate.

Q: When was each part released?

A: The NVIDIA N1 20SM has a release date of 2026-05-31 and is marked as active in production. The AMD Instinct MI455X has a release date of 2026-07-22 and has no production status listed.

The Verdict

The data identifies two fundamentally different products. The AMD Instinct MI455X is a massive compute accelerator: 157.3 TFLOPS FP32, 23.3 TB/s memory bandwidth, 432 GB of HBM4, and a 2300 W TDP. It dominates in every raw throughput metric recorded. The NVIDIA N1 20SM is an integrated graphics processor: 12.01 TFLOPS FP32, 273.2 GB/s bandwidth, 128 GB of LPDDR5X, 20 ray tracing cores, 80 tensor cores, and a single HDMI output.

Workloads that demand dense parallel compute, large memory capacity, or extreme bandwidth should favor the MI455X. The 13.1x FP32 advantage and 85.3x bandwidth advantage are decisive for data-parallel tasks. The absence of ROPs and display outputs confirms the MI455X is not designed for rasterization or graphics output.

Workloads that require rasterization, ray tracing, or tensor acceleration should favor the N1 20SM. The 56.30 GPixel/s pixel rate, 20 ray tracing cores, and 80 tensor cores provide capabilities the MI455X does not offer in the recorded data. The N1 20SM also fits a smaller physical footprint with a 382 mm² die versus 2990 mm².

The MI455X uses a newer process node, 2 nm versus 5 nm, and a wider PCIe interface, 6.0 x16 versus 5.0 x16. The N1 20SM has a higher boost clock relative to base, 2346 MHz versus 741 MHz, giving a 3.2x boost ratio compared to 2.4x for the AMD part. However, the absolute boost clock of the MI455X, 2400 MHz, exceeds the N1 20SM boost of 2346 MHz.

The MI455X has no production status listed, while the N1 20SM is active. The AMD part has a predecessor, Radeon Instinct, while the NVIDIA part has none. The MI455X released on 2026-07-22, the N1 20SM on 2026-05-31.

Neither part has benchmark scores in the database, so selection must rest on specification alignment. The MI455X targets compute-heavy, memory-bound, power-hungry environments. The N1 20SM targets integrated, feature-rich, lower-power scenarios. The data supports these distinct roles without ambiguity.