AMD Instinct MI455X vs NVIDIA H20 NVL16 Comparison

AMD Instinct MI455X and NVIDIA H20 NVL16 represent two distinct approaches to server acceleration. The recorded data shows no direct head-to-head benchmark scores, but the specification sheets reveal substantial differences in compute capacity, memory architecture, and power envelope. This analysis relies strictly on the database entries for both accelerators.

Head-to-Head Benchmarks

The database lists no direct benchmark comparisons between the AMD Instinct MI455X and the NVIDIA H20 NVL16. Neither device has recorded benchmark scores, and the wins counter shows zero for both sides. This absence of measured performance data means the analysis must rely on the architectural specifications and raw compute figures provided.

The most striking difference appears in FP32 throughput. The AMD Instinct MI455X delivers 157.3 TFLOPS of FP32 performance, while the NVIDIA H20 NVL16 provides 39.54 TFLOPS. This places the AMD accelerator approximately 3.98 times ahead in single-precision floating-point work. The delta is substantial and suggests a clear advantage for workloads that rely heavily on FP32 calculations, such as scientific simulations or certain data processing tasks.

FP16 performance tells a different story depending on the metric used. The MI455X achieves 157.3 TFLOPS in FP16 with a 1:1 ratio, meaning the FP16 throughput matches its FP32 figure. The H20 NVL16 reaches 79.07 TFLOPS in FP16 with a 2:1 ratio, where the FP16 rate doubles the FP32 rate. In absolute FP16 terms, the AMD part leads by a factor of roughly 1.99. However, the NVIDIA accelerator's FP16 capability represents a 2.0x gain over its own FP32 output, indicating an architecture optimized for mixed-precision workloads relative to its base compute.

Memory bandwidth further separates the two. The MI455X reports 23.3 TB/s of bandwidth from its 432 GB HBM4 memory stack, while the H20 NVL16 provides 4.03 TB/s from 96 GB of HBM3. The AMD part offers 5.78 times the memory bandwidth and 4.5 times the memory capacity. These figures point to very different deployment scenarios. The MI455X appears designed for massive data residency and high-throughput memory access, whereas the H20 NVL16 targets more modest memory requirements.

Pixel and texture rates also diverge sharply. The MI455X lists a pixel rate of 0 MPixel/s and a texture rate of 2,457.6 GTexel/s. The H20 NVL16 shows 47.52 GPixel/s and 617.8 GTexel/s. The NVIDIA part has functional rasterization units, with 24 ROPs, while the AMD accelerator reports zero ROPs. This indicates the MI455X lacks traditional graphics output capabilities entirely, consistent with its EAM Module form factor and no display outputs. The H20 NVL16, while also lacking display outputs, retains some rasterization hardware.

FAQ

Q: Which accelerator has higher FP32 compute?

A: The AMD Instinct MI455X delivers 157.3 TFLOPS of FP32 performance, compared to 39.54 TFLOPS for the NVIDIA H20 NVL16. This makes the AMD part approximately 3.98 times faster in single-precision throughput.

Q: How do the memory configurations differ?

A: The MI455X uses 432 GB of HBM4 memory with a 24576-bit bus and 23.3 TB/s bandwidth. The H20 NVL16 uses 96 GB of HBM3 with a 6144-bit bus and 4.03 TB/s bandwidth. The AMD accelerator offers 4.5 times the capacity and 5.78 times the bandwidth.

Q: What is the FP16 performance on each device?

A: The MI455X achieves 157.3 TFLOPS in FP16 with a 1:1 ratio to FP32. The H20 NVL16 reaches 79.07 TFLOPS in FP16 with a 2:1 ratio. The AMD part has higher absolute FP16 throughput, while the NVIDIA part shows a larger relative gain from FP32 to FP16.

Q: Are these accelerators suitable for graphics rendering?

A: Neither device has display outputs. The MI455X reports 0 MPixel/s pixel rate and zero ROPs, indicating no rasterization pipeline. The H20 NVL16 has a 47.52 GPixel/s pixel rate with 24 ROPs, but still lacks display outputs. Both are compute-oriented server accelerators.

Q: What are the power requirements?

A: The MI455X has a TDP of 2300 W with a suggested PSU of 2700 W. The H20 NVL16 has a TDP of 400 W with a suggested PSU of 800 W. The NVIDIA part consumes substantially less power.

Q: Which architecture uses a newer manufacturing process?

A: The MI455X uses a 2 nm process node, while the H20 NVL16 uses a 5 nm node. Both are fabricated by TSMC. The AMD part also has a larger die at 2990 mm² compared to 814 mm².

Architecture Differences

The AMD Instinct MI455X uses the CDNA 5.0 architecture with the MI450 256CU chip. The NVIDIA H20 NVL16 uses the Hopper architecture with the GH100 chip. These represent fundamentally different design philosophies. CDNA 5.0 focuses on compute density and memory throughput, while Hopper emphasizes balanced compute with tensor operations.

The process node difference is significant. The MI455X uses a 2 nm process, while the H20 NVL16 uses a 5 nm process, both from TSMC. The AMD chip contains 320,000 million transistors on a 2990 mm² die, resulting in a transistor density of 107.0M per mm². The NVIDIA chip contains 80,000 million transistors on an 814 mm² die, with a density of 98.3M per mm². The MI455X has 4 times the transistor count and a die area 3.67 times larger.

Shader configuration diverges completely. The MI455X has 32,768 shading units, 1,024 TMUs, and zero ROPs. The H20 NVL16 has 9,984 shading units, 312 TMUs, and 24 ROPs. The AMD part uses more than 3.28 times the shading units and 3.28 times the TMUs. The NVIDIA part includes 312 tensor cores, while the MI455X lists no tensor core count. This suggests the H20 NVL16 has dedicated tensor hardware for AI workloads, while the MI455X relies on its massive shader array for compute.

Clock speeds favor the NVIDIA part. The H20 NVL16 has a base clock of 1830 MHz and a boost clock of 1980 MHz. The MI455X has a base clock of 1000 MHz and a boost clock of 2400 MHz. The NVIDIA part runs at 1.83 times the base clock of the AMD part, but the AMD part reaches a higher boost clock by 1.21 times. Memory clocks also differ: the MI455X runs at 1900 MHz with 7.6 Gbps effective, while the H20 NVL16 runs at 1313 MHz with 5.3 Gbps effective.

The memory subsystem shows the largest architectural gap. The MI455X uses HBM4 with a 24576-bit bus width, while the H20 NVL16 uses HBM3 with a 6144-bit bus. The AMD part has a bus width 4 times wider. This explains the massive bandwidth difference: 23.3 TB/s versus 4.03 TB/s. The MI455X also has 4.5 times the memory capacity at 432 GB versus 96 GB.

Power and form factor differ dramatically. The MI455X has a TDP of 2300 W and uses an EAM Module slot with no power connectors listed. The H20 NVL16 has a TDP of 400 W and uses an SXM Module slot. The suggested PSU ratings are 2700 W for the AMD part and 800 W for the NVIDIA part. Bus interfaces also differ: the MI455X uses PCIe 6.0 x16, while the H20 NVL16 uses PCIe 5.0 x16.

The Verdict

The recorded data indicates the AMD Instinct MI455X is positioned for maximum compute throughput and memory capacity. Its 157.3 TFLOPS FP32 and 157.3 TFLOPS FP16 put it in a different performance class than the H20 NVL16. The 432 GB memory and 23.3 TB/s bandwidth provide exceptional data handling capabilities. The 2 nm process and 320,000 million transistors suggest a design focused on raw performance without regard for power efficiency.

The NVIDIA H20 NVL16 offers a more balanced profile. Its 39.54 TFLOPS FP32 and 79.07 TFLOPS FP16 are lower, but the 400 W TDP makes it far more power-efficient. The 96 GB memory and 4.03 TB/s bandwidth are modest by comparison. The presence of 312 tensor cores indicates specialized hardware for tensor operations, which the MI455X lacks in its specification sheet.

For workloads that need maximum FP32 or FP16 throughput, the MI455X is the clear choice based on the numbers. For environments with power constraints or where tensor core acceleration matters, the H20 NVL16 has attributes the AMD part does not list. The MI455X has no display outputs and zero ROPs, confirming it is purely a compute accelerator. The H20 NVL16, despite having ROPs and a pixel rate, also lacks display outputs.

The production status differs: the H20 NVL16 is marked as Active, while the MI455X has no production status listed. The release dates place the MI455X in July 2026 and the H20 NVL16 in September 2025. The NVIDIA part has a predecessor (Server Ada) and successor (Server Blackwell), while the AMD part lists Radeon Instinct as its predecessor.

Specification Differences

The two accelerators differ in every major specification category. The MI455X uses the CDNA 5.0 architecture with a 2 nm process, while the H20 NVL16 uses Hopper with a 5 nm process. Transistor counts are 320,000 million versus 80,000 million. Die sizes are 2990 mm² versus 814 mm². Transistor densities are 107.0M per mm² versus 98.3M per mm².

Clock speeds show the MI455X at 1000 MHz base and 2400 MHz boost, compared to 1830 MHz base and 1980 MHz boost for the H20 NVL16. Memory clocks are 1900 MHz with 7.6 Gbps effective for the AMD part, versus 1313 MHz with 5.3 Gbps effective for the NVIDIA part. Memory sizes are 432 GB versus 96 GB, types are HBM4 versus HBM3, bus widths are 24576 bit versus 6144 bit, and bandwidths are 23.3 TB/s versus 4.03 TB/s.

Shading units total 32,768 for the MI455X and 9,984 for the H20 NVL16. TMUs are 1,024 versus 312. ROPs are 0 versus 24. The H20 NVL16 has 312 tensor cores, while the MI455X lists none. Pixel rates are 0 MPixel/s versus 47.52 GPixel/s. Texture rates are 2,457.6 GTexel/s versus 617.8 GTexel/s. FP32 is 157.3 TFLOPS versus 39.54 TFLOPS. FP16 is 157.3 TFLOPS versus 79.07 TFLOPS.

TDP values are 2300 W versus 400 W. Slot widths are EAM Module versus SXM Module. The MI455X lists no power connectors, while the H20 NVL16 has no connector data. Suggested PSUs are 2700 W versus 800 W. Bus interfaces are PCIe 6.0 x16 versus PCIe 5.0 x16. Both have no display outputs. DirectX, OpenGL, and Vulkan support are listed as N/A for both.

Where Each One Wins

The AMD Instinct MI455X wins decisively in raw compute throughput. Its FP32 performance of 157.3 TFLOPS is 3.98 times higher than the H20 NVL16's 39.54 TFLOPS. Its FP16 performance of 157.3 TFLOPS is 1.99 times higher than the NVIDIA part's 79.07 TFLOPS. Texture rate favors the AMD part by a factor of 3.98, at 2,457.6 GTexel/s versus 617.8 GTexel/s.

Memory capacity and bandwidth are clear wins for the MI455X. The 432 GB of HBM4 memory is 4.5 times the 96 GB of HBM3 on the H20 NVL16. The 23.3 TB/s bandwidth is 5.78 times the 4.03 TB/s of the NVIDIA part. The 24576-bit bus width is 4 times the 6144-bit width. These figures suggest the MI455X can handle datasets and memory access patterns that would exceed the H20 NVL16's capabilities.

The NVIDIA H20 NVL16 wins in power efficiency and thermal management. Its 400 W TDP is 5.75 times lower than the MI455X's 2300 W TDP. The suggested PSU of 800 W is 3.38 times lower than the 2700 W requirement for the AMD part. This makes the H20 NVL16 easier to integrate into existing server infrastructure without major power delivery upgrades.

Clock speeds also favor the NVIDIA part at base frequency. The 1830 MHz base clock is 1.83 times higher than the MI455X's 1000 MHz base clock. However, the AMD part's 2400 MHz boost clock is 1.21 times higher than the NVIDIA part's 1980 MHz boost clock. The H20 NVL16 also has functional ROPs and a pixel rate, which the MI455X completely lacks.

The tensor core presence on the H20 NVL16 represents a capability the MI455X does not list. With 312 tensor cores, the NVIDIA part has dedicated hardware for tensor operations, which could benefit certain AI and deep learning workloads. The MI455X's specification sheet does not include tensor core data, leaving that comparison undefined.

The production status of the H20 NVL16 as Active, with a successor already identified, indicates an established product. The MI455X has no production status, suggesting it may be earlier in its lifecycle. The release dates show the H20 NVL16 launched first, in September 2025, with the MI455X following in July 2026.