AMD Instinct MI455X vs NVIDIA RTX 4000 Ada Generation Comparison

AMD Instinct MI455X and NVIDIA RTX 4000 Ada Generation occupy opposite ends of the hardware spectrum. The MI455X is a massive accelerator module built for scale-out compute, while the RTX 4000 Ada is a single-slot workstation card with active production status. The database shows no overlapping benchmark scores for the two, so the analysis relies on their recorded specifications, architectural traits, and the RTX 4000 Ada’s measured performance relative to its nearest rivals.

Where Each One Wins

The AMD Instinct MI455X wins on raw compute throughput and memory capacity. Its FP32 figure of 157.3 TFLOPS is roughly 5.9 times the RTX 4000 Ada’s 26.73 TFLOPS, and FP16 performance is identical to its FP32 at 157.3 TFLOPS (1:1), which makes it suited for workloads that tolerate reduced precision. The MI455X carries 432 GB of HBM4 memory on a 24576-bit bus, yielding 23.3 TB/s of bandwidth. That is over 64 times the bandwidth of the RTX 4000 Ada’s 360.0 GB/s. Texture rate also favors AMD, with 2,457.6 GTexel/s versus 417.6 GTexel/s.

The NVIDIA RTX 4000 Ada Generation wins on practical integration and workstation features. It is a single-slot card measuring 245 mm in length, with 4x DisplayPort 1.4a outputs, while the MI455X has no display outputs. The RTX 4000 Ada supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4, whereas the MI455X lists N/A for all three APIs. The RTX 4000 Ada also has dedicated ray tracing cores (48) and tensor cores (192), features absent from the MI455X’s specification list. Its pixel rate of 139.2 GPixel/s is concrete, while the MI455X is recorded at 0 MPixel/s. The RTX 4000 Ada is the only one of the two with benchmark results in the database, scoring 146,593 in Geekbench OpenCL and 123,842 in Geekbench Vulkan, with an average benchmark score of 135,218 and a 95th percentile ranking among all GPUs.

The Verdict

The recorded data points to two distinct buyers. The AMD Instinct MI455X is for compute environments that need extreme FP32/FP16 throughput and enormous memory bandwidth, with no need for display output or conventional graphics APIs. The NVIDIA RTX 4000 Ada Generation is for workstation users who need a compact, active card with display outputs, ray tracing, tensor cores, and full graphics API support.

The MI455X’s 2300 W TDP and suggested PSU of 2700 W place it in a different operating envelope than the RTX 4000 Ada’s 130 W TDP and 300 W suggested PSU. The RTX 4000 Ada uses a single 16-pin power connector; the MI455X lists no power connectors, as it is an EAM Module. The RTX 4000 Ada is the practical choice for a desktop workstation. The MI455X is a system-level component for high-performance computing racks.

Benchmark data reinforces the RTX 4000 Ada’s workstation positioning. Its average score of 135,218 places it at the 95th percentile of all GPUs in the database, and its nearest rivals are all within a narrow band: NVIDIA A10M at 135,230 (0% delta), AMD Radeon PRO W6800 at 135,396 (-0.1%), AMD Radeon Pro W6800X Duo at 135,774 (-0.4%), and AMD Radeon PRO V620 at 136,472 (-0.9%). The MI455X has no benchmark entries and no nearest rivals recorded, so its percentile of 50 reflects an absence of measured data rather than a performance verdict.

Head-to-Head Benchmarks

There are no direct head-to-head benchmark results in the database for these two products. The comparison must be made from specification-level figures and the RTX 4000 Ada’s own benchmark record.

The largest win for the MI455X is memory bandwidth. At 23.3 TB/s, it exceeds the RTX 4000 Ada’s 360.0 GB/s by a factor of roughly 64.7. Memory capacity follows the same pattern: 432 GB versus 20 GB. The bus width difference is equally stark, 24576 bit versus 160 bit, and the memory type differs entirely, HBM4 versus GDDR6.

FP32 compute is another decisive MI455X advantage. The 157.3 TFLOPS figure is about 5.88 times the RTX 4000 Ada’s 26.73 TFLOPS. FP16 is identical to FP32 on both cards, so the ratio holds there as well. Texture rate favors AMD at 2,457.6 GTexel/s versus 417.6 GTexel/s, a factor of roughly 5.89.

The RTX 4000 Ada wins on the features that matter for conventional graphics work. It has 64 ROPs and a pixel rate of 139.2 GPixel/s, while the MI455X lists 0 ROPs and 0 MPixel/s. The RTX 4000 Ada has 48 ray tracing cores and 192 tensor cores; the MI455X lists neither. The RTX 4000 Ada’s 6144 shading units, 192 TMUs, and 64 ROPs are standard workstation counts, while the MI455X’s 32768 shading units and 1024 TMUs are oriented toward raw shader throughput.

Clock speeds also differ. The MI455X runs at a 1000 MHz base and 2400 MHz boost, while the RTX 4000 Ada runs at 1500 MHz base and 2175 MHz boost. The RTX 4000 Ada has the higher base clock, but the MI455X has the higher boost clock. Memory clocks diverge sharply: 1900 MHz (7.6 Gbps effective) for the MI455X versus 2250 MHz (18 Gbps effective) for the RTX 4000 Ada. The effective memory speed advantage goes to NVIDIA, but the bandwidth advantage goes to AMD because of the vastly wider bus.

FAQ

Q: Which card has higher FP32 performance?

A: The AMD Instinct MI455X records 157.3 TFLOPS FP32, compared to the NVIDIA RTX 4000 Ada Generation’s 26.73 TFLOPS.

Q: Does the RTX 4000 Ada Generation support display outputs?

A: Yes, it has 4x DisplayPort 1.4a outputs. The AMD Instinct MI455X lists no display outputs.

Q: What is the memory bandwidth difference?

A: The MI455X has 23.3 TB/s of bandwidth from 432 GB of HBM4 on a 24576-bit bus. The RTX 4000 Ada has 360.0 GB/s from 20 GB of GDDR6 on a 160-bit bus.

Q: How does the RTX 4000 Ada Generation perform in Geekbench?

A: It scores 146,593 in Geekbench OpenCL and 123,842 in Geekbench Vulkan, with an average benchmark score of 135,218.

Q: What is the power requirement for each card?

A: The MI455X has a 2300 W TDP and a suggested PSU of 2700 W. The RTX 4000 Ada has a 130 W TDP and a suggested PSU of 300 W.

Q: Which card has ray tracing support?

A: The NVIDIA RTX 4000 Ada Generation lists 48 ray tracing cores. The AMD Instinct MI455X does not list ray tracing cores.

Architecture Differences

The two cards use fundamentally different architectures. The AMD Instinct MI455X is built on CDNA 5.0, while the NVIDIA RTX 4000 Ada Generation uses Ada Lovelace. The MI455X is based on the MI450 256CU chip, and the RTX 4000 Ada uses the AD104 chip.

Process nodes differ: the MI455X is on a 2 nm TSMC process, while the RTX 4000 Ada is on a 5 nm TSMC process. Transistor counts diverge massively. The MI455X has 320,000 million transistors on a 2990 mm² die, giving a transistor density of 107.0M per mm². The RTX 4000 Ada has 35,800 million transistors on a 294 mm² die, giving a higher density of 121.8M per mm².

Memory architecture is completely different. The MI455X uses HBM4 with a 24576-bit bus, while the RTX 4000 Ada uses GDDR6 with a 160-bit bus. The MI455X has no display outputs, no ray tracing cores, and no tensor cores listed. The RTX 4000 Ada has 48 ray tracing cores, 192 tensor cores, and 4x DisplayPort 1.4a outputs.

API support separates the two as well. The MI455X lists DirectX, OpenGL, and Vulkan as N/A. The RTX 4000 Ada supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. The MI455X is an EAM Module with no power connectors, while the RTX 4000 Ada is a single-slot card with a 16-pin connector.

Specification Differences

The bus interface differs: the MI455X uses PCIe 6.0 x16, while the RTX 4000 Ada uses PCIe 4.0 x16.

Shading units: 32768 on the MI455X versus 6144 on the RTX 4000 Ada. TMUs: 1024 versus 192. ROPs: 0 versus 64. The RTX 4000 Ada has 48 ray tracing cores and 192 tensor cores; the MI455X lists none.

Base clocks: 1000 MHz for the MI455X versus 1500 MHz for the RTX 4000 Ada. Boost clocks: 2400 MHz versus 2175 MHz. Memory clocks: 1900 MHz (7.6 Gbps effective) versus 2250 MHz (18 Gbps effective).

Memory: 432 GB HBM4 versus 20 GB GDDR6. Bus width: 24576 bit versus 160 bit. Bandwidth: 23.3 TB/s versus 360.0 GB/s.

Pixel rate: 0 MPixel/s versus 139.2 GPixel/s. Texture rate: 2,457.6 GTexel/s versus 417.6 GTexel/s.

TDP: 2300 W versus 130 W. Suggested PSU: 2700 W versus 300 W. Slot width: EAM Module versus single-slot. Power connectors: none versus 1x 16-pin.

Dimensions: the RTX 4000 Ada is 245 mm long and 112 mm high. The MI455X has no recorded dimensions.

Release dates: the MI455X is dated 2026-07-22, while the RTX 4000 Ada is dated 2023-08-08 and is marked as Active. The MI455X’s predecessor is Radeon Instinct; the RTX 4000 Ada’s predecessor is Workstation Ampere and its successor is Blackwell PRO W. The RTX 4000 Ada carries the GeForce 40-series series name, while the MI455X belongs to the Instinct (MIx) generation.