AMD Instinct MI455X vs NVIDIA RTX PRO 4500 Blackwell Server Comparison

Head-to-Head Benchmarks

The recorded database contains no direct head-to-head benchmark results for the AMD Instinct MI455X and the NVIDIA RTX PRO 4500 Blackwell Server. Both entries show zero benchmark scores, zero wins for either side, and no nearest rival data. The percentileVsAllGpus field places both parts at the 50th percentile, though this reflects their position among all tracked GPUs in the absence of measured workloads.

Without measured performance data, the comparison must rely entirely on the architectural specifications recorded in the database. The most striking contrast appears in raw compute throughput. The AMD Instinct MI455X delivers 157.3 TFLOPS of FP32 and FP16 performance, while the NVIDIA RTX PRO 4500 Blackwell Server delivers 50.70 TFLOPS in both precision formats. This indicates the AMD part holds a 3.1x advantage in peak floating-point throughput, assuming both architectures sustain their rated specifications.

Memory bandwidth tells a similar story. The MI455X accesses 432 GB of HBM4 memory across a 24576-bit bus, producing 23.3 TB/s of bandwidth. The RTX PRO 4500 uses 32 GB of GDDR7 on a 256-bit bus, yielding 800.3 GB/s. The AMD solution provides roughly 29x more memory bandwidth and 13.5x more memory capacity, which would strongly favor large matrix operations and data-intensive inference workloads if benchmarked.

Texture and pixel rates also diverge sharply. The MI455X reaches 2,457.6 GTexel/s with zero pixel output, reflecting its compute-focused design without a rasterization pipeline. The NVIDIA part achieves 792.1 GTexel/s and 270.5 GPixel/s, indicating it retains full graphics functionality despite its server positioning. The absence of ROPs on the AMD side confirms it is not designed for display or raster workloads.

Clock behavior differs meaningfully. The NVIDIA part runs at a 1215 MHz base and 2415 MHz boost, while the AMD part operates at 1000 MHz base and 2400 MHz boost. Despite the similar boost clocks, the AMD part achieves its higher throughput through 32,768 shading units versus 10,496 on the NVIDIA chip, combined with 1,024 TMUs versus 328.

Architecture Differences

The two accelerators represent fundamentally different design philosophies within their respective architectures. The AMD Instinct MI455X uses CDNA 5.0, built on a 2 nm TSMC process. The database records 320,000 million transistors on a 2990 mm² die, producing a transistor density of 107.0M per mm². This is an enormous chip, nearly eight times the die area of the NVIDIA part.

The NVIDIA RTX PRO 4500 Blackwell Server uses Blackwell 2.0 architecture on a 5 nm TSMC process. It integrates 45,600 million transistors on a 378 mm² die, achieving a higher transistor density of 120.6M per mm². The density advantage reflects the more mature 5 nm node and the different circuit structures required for a full graphics and compute pipeline.

Memory architecture separates these parts completely. The MI455X uses HBM4 stacked memory with a 24576-bit interface, the widest memory bus recorded in the comparison. This enables the 23.3 TB/s bandwidth figure. The NVIDIA part uses GDDR7 with a 256-bit bus, a conventional discrete memory layout that caps bandwidth at 800.3 GB/s. The AMD part's memory clock runs at 1900 MHz with 7.6 Gbps effective data rate, while the NVIDIA memory operates at 1563 MHz with 25 Gbps effective.

The compute pipelines diverge on features. The MI455X lists no raster operations units, no ray tracing cores, and no tensor cores in the database. Its API support is marked N/A for DirectX, OpenGL, and Vulkan. The NVIDIA part includes 82 RT cores and 328 tensor cores, supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4, and has 112 ROPs for pixel output.

Power and physical design differ dramatically. The MI455X consumes 2300 W TDP and requires a 2700 W suggested power supply. It uses no power connectors, instead mounting as an EAM Module. The NVIDIA part draws 165 W TDP with a 450 W suggested power supply, using a single 16-pin connector in a single-slot form factor. The RTX PRO 4500 measures 267 mm in length, 111 mm in height, and 40 mm in width. The MI455X dimensions are not recorded.

Both parts use PCIe interfaces, with the MI455X on PCIe 6.0 x16 and the NVIDIA part on PCIe 5.0 x16. Neither provides display outputs. Release timing shows the NVIDIA part arriving first on 2026-03-16, with the AMD part following on 2026-07-22. The NVIDIA part has an active production status and lists Server Hopper as its predecessor and Server Rubin as its successor. The AMD part lists Radeon Instinct as its predecessor with no successor recorded.

Where Each One Wins

The recorded data supports distinct use-case advantages for each accelerator, based on architectural strengths rather than measured benchmarks.

The AMD Instinct MI455X wins decisively in raw compute throughput and memory capacity. Its 157.3 TFLOPS FP32 performance, 432 GB HBM4 memory, and 23.3 TB/s bandwidth position it for large-scale compute workloads that saturate memory and arithmetic units. The 2,457.6 GTexel/s texture rate suggests strong performance in texture-heavy compute tasks, though the absence of ROPs means no display output or rasterization capability. This part targets dense matrix operations, large model inference, and scientific computing where memory capacity and bandwidth dominate.

The NVIDIA RTX PRO 4500 Blackwell Server wins in efficiency and feature completeness. Its 165 W TDP against 2300 W represents a 13.9x power advantage. The 50.70 TFLOPS FP32 throughput per 165 W yields a far better performance-per-watt profile, though the database does not record a formal efficiency metric. The inclusion of RT cores, tensor cores, and full graphics API support means this part can handle ray tracing, tensor operations, and traditional graphics workloads alongside compute. The 270.5 GPixel/s pixel rate and 112 ROPs confirm rasterization capability.

The NVIDIA part also wins on physical integration flexibility. Its single-slot design, 267 mm length, and standard 16-pin power connector allow installation in conventional server chassis. The AMD part's EAM Module form factor and 2300 W TDP require specialized cooling and power delivery infrastructure. The NVIDIA part's PCIe 5.0 interface, while one generation behind the AMD part's PCIe 6.0, still provides substantial bandwidth for most server applications.

Process efficiency favors NVIDIA. The 120.6M transistors per mm² density on a 5 nm node, combined with the smaller 378 mm² die, indicates a more compact implementation. The AMD part's 107.0M per mm² density on a 2 nm node produces a much larger chip with higher absolute transistor count, but the density figure shows the NVIDIA design packs transistors more tightly.

The Verdict

The data presents a clear split between two different accelerator classes. The AMD Instinct MI455X is a massive compute engine built for maximum throughput and memory capacity. Its 157.3 TFLOPS FP32, 23.3 TB/s bandwidth, and 432 GB HBM4 memory place it in a category for workloads that require extreme scale, such as large language model training, scientific simulation, or data center inference with enormous model footprints. The absence of graphics capabilities and the 2300 W TDP confirm this is not a general-purpose server GPU.

The NVIDIA RTX PRO 4500 Blackwell Server is a versatile, efficient accelerator that retains full graphics functionality. Its 50.70 TFLOPS FP32, 800.3 GB/s bandwidth, and 32 GB GDDR7 memory suit it for professional visualization, mixed compute and graphics workloads, and applications that benefit from RT cores and tensor cores. The 165 W TDP makes it deployable in standard servers without specialized power or cooling infrastructure.

The recorded data shows no benchmark scores for either part, so performance claims cannot be validated against actual workloads. The comparison rests entirely on specification analysis. For pure compute density and memory scale, the MI455X dominates. For efficiency, feature breadth, and deployment flexibility, the RTX PRO 4500 leads.

The release dates indicate the NVIDIA part shipped first on 2026-03-16, with the AMD part following on 2026-07-22. The NVIDIA part's active production status and defined successor suggest an ongoing product lifecycle. The AMD part's predecessor relationship to Radeon Instinct and lack of successor indicate a newer entry in its lineage.

FAQ

Q: Which GPU has higher FP32 compute performance?

A: The AMD Instinct MI455X delivers 157.3 TFLOPS FP32, while the NVIDIA RTX PRO 4500 Blackwell Server delivers 50.70 TFLOPS FP32.

Q: How much memory does each accelerator have?

A: The AMD Instinct MI455X has 432 GB of HBM4 memory with 23.3 TB/s bandwidth. The NVIDIA RTX PRO 4500 has 32 GB of GDDR7 memory with 800.3 GB/s bandwidth.

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

A: Only the NVIDIA RTX PRO 4500 lists 82 RT cores and 328 tensor cores. The AMD Instinct MI455X records no RT cores or tensor cores.

Q: What are the power requirements for each part?

A: The AMD Instinct MI455X has a 2300 W TDP with a 2700 W suggested power supply. The NVIDIA RTX PRO 4500 has a 165 W TDP with a 450 W suggested power supply.

Q: Which accelerator supports display outputs?

A: Neither part provides display outputs. Both are server-focused accelerators without video output capabilities.

Q: What process nodes are used for each chip?

A: The AMD Instinct MI455X uses a 2 nm TSMC process with 320,000 million transistors. The NVIDIA RTX PRO 4500 uses a 5 nm TSMC process with 45,600 million transistors.