AMD Instinct MI455X vs AMD Radeon PRO W7800 Comparison

The Verdict

The AMD Instinct MI455X and AMD Radeon PRO W7800 serve entirely different purposes, and the data makes that split clear. The Instinct MI455X is a compute accelerator with no display outputs, a 2300 W TDP, and a 432 GB HBM4 memory pool, placing it in the 50th percentile of all GPUs with an average benchmark score of 0 in the database. The Radeon PRO W7800 is a workstation card with 32 GB GDDR6, three DisplayPort 2.1 outputs plus one mini-DisplayPort 2.1, a 260 W TDP, and it sits in the 97th percentile with an average benchmark score of 164894. Users who need a professional visualization card with monitor outputs and standard PCIe 4.0 compatibility should pick the W7800. Users who need raw compute throughput and massive memory capacity for server-side workloads should pick the MI455X, provided their infrastructure can support its power and cooling requirements.

Architecture Differences

The MI455X uses the CDNA 5.0 architecture on a 2 nm TSMC process, while the W7800 uses RDNA 3.0 on a 5 nm TSMC process. The MI455X features the MI450 256CU chip, which contains 320,000 million transistors on a 2990 mm² die, resulting in a transistor density of 107.0M per mm². The W7800 features the Navi 31 chip, codenamed Plum Bonito, with 57,700 million transistors on a 529 mm² die, achieving a density of 109.1M per mm². Both use TSMC as the foundry, but the MI455X node is two process generations ahead.

The MI455X has 32768 shading units, 1024 texture mapping units, and zero ROPs, reflecting its compute-only design. The W7800 has 4480 shading units, 280 TMUs, 128 ROPs, and 70 ray accelerators. The MI455X supports no DirectX, OpenGL, or Vulkan APIs, while the W7800 supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. The MI455X is an EAM Module with no power connectors and no display outputs, while the W7800 is a dual-slot card with two 8-pin power connectors and four display outputs.

Memory architecture differs fundamentally. The MI455X uses 432 GB of HBM4 on a 24576-bit bus with 23.3 TB/s bandwidth, clocked at 1900 MHz (7.6 Gbps effective). The W7800 uses 32 GB of GDDR6 on a 256-bit bus with 576.0 GB/s bandwidth, clocked at 2250 MHz (18 Gbps effective). The MI455X memory bandwidth is roughly 40 times higher, but the W7800 memory is conventional and far easier to integrate into a standard workstation build.

FAQ

Q: Which card has higher raw FP32 compute throughput?

A: The MI455X delivers 157.3 TFLOPS FP32, which is approximately 3.5 times the W7800's 45.25 TFLOPS FP32.

Q: Does the MI455X support any display outputs?

A: No. The MI455X has no display outputs, while the W7800 provides 3x DisplayPort 2.1 and 1x mini-DisplayPort 2.1.

Q: What is the memory capacity difference?

A: The MI455X has 432 GB of HBM4 memory, while the W7800 has 32 GB of GDDR6. The MI455X also has a 24576-bit bus versus the W7800's 256-bit bus.

Q: Which card has a higher boost clock?

A: The W7800 boosts to 2525 MHz, while the MI455X boosts to 2400 MHz. The W7800 also has a higher base clock at 1895 MHz versus 1000 MHz.

Q: What is the power consumption difference?

A: The MI455X has a 2300 W TDP with a suggested PSU of 2700 W, while the W7800 has a 260 W TDP with a suggested PSU of 600 W.

Q: Which card supports PCIe 5.0 or newer?

A: The MI455X uses PCIe 6.0 x16, while the W7800 uses PCIe 4.0 x16. The MI455X is two generations ahead in bus interface.

Q: When were these cards released?

A: The MI455X released on 2026-07-22, while the W7800 released on 2023-04-12. The W7800 is currently marked as Active in production status.

Specification Differences

The table below highlights only the fields where the two cards differ:

| Specification | MI455X | W7800 |

|---|---|---|

| Architecture | CDNA 5.0 | RDNA 3.0 |

| Codename | None | Plum Bonito |

| Process Node | 2 nm | 5 nm |

| Transistors | 320,000 million | 57,700 million |

| Die Size | 2990 mm² | 529 mm² |

| Transistor Density | 107.0M / mm² | 109.1M / mm² |

| Base Clock | 1000 MHz | 1895 MHz |

| Boost Clock | 2400 MHz | 2525 MHz |

| Memory Clock | 1900 MHz 7.6 Gbps effective | 2250 MHz 18 Gbps effective |

| Memory Size | 432 GB | 32 GB |

| Memory Type | HBM4 | GDDR6 |

| Memory Bus Width | 24576 bit | 256 bit |

| Memory Bandwidth | 23.3 TB/s | 576.0 GB/s |

| Shading Units | 32768 | 4480 |

| TMUs | 1024 | 280 |

| ROPs | 0 | 128 |

| RT Cores | None | 70 |

| Pixel Rate | 0 MPixel/s | 323.2 GPixel/s |

| Texture Rate | 2,457.6 GTexel/s | 707.0 GTexel/s |

| FP32 | 157.3 TFLOPS | 45.25 TFLOPS |

| FP16 | 157.3 TFLOPS (1:1) | 90.50 TFLOPS (2:1) |

| TDP | 2300 W | 260 W |

| Slot Width | EAM Module | Dual-slot |

| Power Connectors | None | 2x 8-pin |

| Suggested PSU | 2700 W | 600 W |

| Bus Interface | PCIe 6.0 x16 | PCIe 4.0 x16 |

| Display Outputs | No outputs | 3x DisplayPort 2.1, 1x mini-DisplayPort 2.1 |

| DirectX | N/A | 12 Ultimate (12_2) |

| OpenGL | N/A | 4.6 |

| Vulkan | N/A | 1.4 |

| Dimensions | Not listed | 280 mm x 110 mm x 40 mm |

| Release Date | 2026-07-22 | 2023-04-12 |

| Predecessor | Radeon Instinct | Radeon Pro Vega |

| Launch MSRP | Not listed | 2,499 USD |

Head-to-Head Benchmarks

The head-to-head benchmark table between the MI455X and W7800 is empty in the database, meaning no direct comparative tests were recorded. However, the W7800 has individual benchmark scores: 154366 in Geekbench OpenCL and 175422 in Geekbench Vulkan, giving it an average benchmark score of 164894. The MI455X has no recorded benchmarks and an average score of 0.

The W7800's percentile ranking of 97 versus the MI455X's 50 reflects this data gap. The MI455X sits in the middle of all GPUs in the database, but this is a placeholder value rather than a measured result, since no benchmark runs exist for it. The W7800, by contrast, has real measurements that place it near the top of the database.

Comparing the W7800 to its nearest rivals puts its performance in context. The NVIDIA RTX A5500 scores 165217 on average, which is 0.2% ahead of the W7800. The NVIDIA RTX 4500 Ada Generation scores 166094, 0.7% ahead. The NVIDIA A100 PCIe 40 GB scores 162504, which is 1.5% behind the W7800. The AMD Radeon Pro W6900X scores 168574, 2.2% ahead. The W7800 thus sits in a tight cluster of high-end professional cards, all within roughly 2 percentage points of each other.

Where Each One Wins

The MI455X wins decisively in compute-heavy, memory-hungry workloads. Its 157.3 TFLOPS FP32 output is more than three times the W7800's 45.25 TFLOPS. Its 432 GB HBM4 memory with 23.3 TB/s bandwidth dwarfs the W7800's 32 GB GDDR6 with 576.0 GB/s, making it the clear choice for large model training, scientific simulation, or any task that needs to hold massive datasets on the accelerator itself. Its FP16 throughput of 157.3 TFLOPS (1:1 ratio) also exceeds the W7800's 90.50 TFLOPS (2:1 ratio), meaning the MI455X does not rely on packed math to achieve high FP16 rates. The PCIe 6.0 x16 interface provides double the bus bandwidth of the W7800's PCIe 4.0 x16, reducing data transfer bottlenecks for host-to-device communication.

The W7800 wins in every scenario that requires a display, standard software support, or reasonable power draw. It has 70 ray accelerators for hardware-accelerated ray tracing, 128 ROPs for rasterization, and a 323.2 GPixel/s pixel rate, all of which are absent on the MI455X. It supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4, while the MI455X supports none of these APIs. Its 260 W TDP and 600 W suggested PSU fit into a conventional workstation, whereas the MI455X requires a 2700 W PSU and an EAM Module form factor. The W7800 also has a higher boost clock at 2525 MHz versus 2400 MHz, and a higher base clock at 1895 MHz versus 1000 MHz, indicating better clock scaling for latency-sensitive tasks.

For real-world professional work, the W7800's measured benchmark scores confirm its capability. Its Geekbench Vulkan score of 175422 exceeds its OpenCL score of 154366, suggesting strong driver optimization for modern graphics APIs. The MI455X has no such measurements, so its compute advantage remains theoretical in the database until benchmarks are recorded. The W7800's 2,499 USD launch MSRP positions it as a conventional high-end workstation purchase, while the MI455X has no listed MSRP, consistent with its server-class role.

In summary, the MI455X is for compute farms that prioritize throughput and memory capacity above all else. The W7800 is for engineers, designers, and researchers who need a physical card that outputs video, runs standard APIs, and delivers strong professional performance within a normal power envelope. The data shows two cards that share a manufacturer but little else.