AMD Instinct MI455X vs AMD Radeon RX 7700 XT Comparison

The Verdict

The database comparison between the AMD Instinct MI455X and the AMD Radeon RX 7700 XT is defined by a fundamental divide in purpose and architecture. The RX 7700 XT is a conventional consumer graphics card with a complete set of benchmark scores, a 67th percentile placement against all GPUs, and an average benchmark score of 22,549. The MI455X, by contrast, is an accelerator module with no recorded benchmarks, a 50th percentile placement, and an average benchmark score of zero. The data shows these are not competing products; they serve entirely different segments of the hardware landscape.

The RX 7700 XT is the only one of the two with measurable graphics performance. Its recorded scores span DirectX 10, 11, 12, and 9 tests, plus OpenCL, Vulkan, and compute workloads. The MI455X has no such measurements in the database. For any graphics workload, the RX 7700 XT is the sole option with data. For compute tasks that leverage massive memory capacity and bandwidth, the MI455X presents a specification sheet that dwarfs the RX 7700 XT in several raw parameters, but no recorded performance confirms that advantage.

The verdict from the recorded data is straightforward: the RX 7700 XT is the choice for anyone requiring actual benchmark-verified graphics or compute performance. The MI455X is the choice for workloads that demand the highest possible memory capacity, bus width, and memory bandwidth, based purely on its specifications. The RX 7700 XT's nearest rivals in the database include the NVIDIA GeForce RTX 5060 Mobile (0.5% higher average score), the NVIDIA GeForce RTX 4060 Mobile (0.8% lower), the NVIDIA GeForce RTX 2080 (1.5% lower), and the AMD Radeon RX 5700 (1.7% higher). This places the RX 7700 XT in a tightly clustered performance band.

Architecture Differences

The architectural split between these two AMD parts is stark. The MI455X uses CDNA 5.0 architecture on a 2 nm process node from TSMC, with a chip designated MI450 256CU. The RX 7700 XT uses RDNA 3.0 architecture on a 5 nm process node, also from TSMC, with a Navi 32 chip and the codename Wheat Nas. The MI455X belongs to the Instinct (MIx) generation, while the RX 7700 XT belongs to the Navi III (RX 7000) generation.

The transistor counts diverge dramatically. The MI455X packs 320,000 million transistors on a die size of 2990 mm², yielding a transistor density of 107.0 million per square millimeter. The RX 7700 XT contains 28,100 million transistors on a 346 mm² die, with a density of 81.2 million per square millimeter. The MI455X has roughly eleven times the transistor count and a die more than eight times larger.

Memory architecture is another major differentiator. The MI455X uses 432 GB of HBM4 memory on a 24576-bit bus, providing 23.3 TB/s of bandwidth. The RX 7700 XT uses 12 GB of GDDR6 memory on a 192-bit bus, delivering 432.0 GB/s. The MI455X's memory bandwidth is more than fifty times higher, and its capacity is 36 times greater. The memory clock for the MI455X is 1900 MHz (7.6 Gbps effective), while the RX 7700 XT runs at 2250 MHz (18 Gbps effective).

Compute resources show the MI455X's scale advantage. It has 32,768 shading units and 1,024 texture mapping units, with zero ROPs. The RX 7700 XT has 3,456 shading units, 216 TMUs, and 96 ROPs. The MI455X has no ray tracing cores listed, while the RX 7700 XT has 54 RT cores. The MI455X has no display outputs, no graphics API support (DirectX, OpenGL, and Vulkan all listed as N/A), and uses a PCIe 6.0 x16 interface. The RX 7700 XT supports DirectX 12 Ultimate (12_2), OpenGL 4.6, Vulkan 1.4, and uses PCIe 4.0 x16.

Head-to-Head Benchmarks

The head-to-head benchmark table in the database is empty, with zero wins recorded for either part. This means no direct comparative measurements exist between the MI455X and the RX 7700 XT. The MI455X has no individual benchmark entries at all, so there is no data to compare against the RX 7700 XT's ten recorded tests.

The RX 7700 XT's benchmark results provide the only quantitative performance data available. Its highest score comes from Geekbench OpenCL at 138,383. The PassMark G3D score is 22,547, and the PassMark GPU Compute score is 12,912. In graphics API tests, the PassMark DirectX 9 score is 294, DirectX 11 is 232, and DirectX 10 is 119. The PassMark DirectX 12 score is 79. Vulkan performance in Geekbench is 46,443, and the 3DMark Steel Nomad DX12 test yields 3,316. The PassMark G2D score is 1,161.

The MI455X offers no scores to compare. Its texture rate of 2,457.6 GTexel/s and FP32 performance of 157.3 TFLOPS (with FP16 at the same 157.3 TFLOPS at a 1:1 ratio) are specification values that indicate raw compute capability, but the database records no benchmark verification. The RX 7700 XT's FP32 is 35.17 TFLOPS, with FP16 also at 35.17 TFLOPS at 1:1. The MI455X's FP32 figure is roughly 4.5 times higher on paper, and its texture rate is about 4.5 times higher as well. The pixel rate for the MI455X is 0 MPixel/s because it has no ROPs, while the RX 7700 XT achieves 244.2 GPixel/s.

FAQ

Q: Which GPU has higher benchmark scores in the database?

A: The AMD Radeon RX 7700 XT is the only one with recorded benchmark scores. Its average benchmark score is 22,549, with a 67th percentile placement against all GPUs. The AMD Instinct MI455X has an average benchmark score of 0 and no recorded benchmarks.

Q: What is the memory capacity difference between the two?

A: The MI455X has 432 GB of HBM4 memory, while the RX 7700 XT has 12 GB of GDDR6 memory. The MI455X's memory bus is 24,576 bits wide compared to the RX 7700 XT's 192-bit bus, and memory bandwidth is 23.3 TB/s versus 432.0 GB/s.

Q: How do the power requirements compare?

A: The MI455X has a TDP of 2,300 W with a suggested PSU of 2,700 W and no power connectors (it uses an EAM Module slot). The RX 7700 XT has a TDP of 245 W, a suggested PSU of 550 W, and uses 2x 8-pin power connectors.

Q: What display outputs does each GPU support?

A: The MI455X has no display outputs at all. The RX 7700 XT has 1x HDMI 2.1a, 2x DisplayPort 2.1, and 1x USB Type-C.

Q: Which GPU has a higher shading unit count?

A: The MI455X has 32,768 shading units, compared to the RX 7700 XT's 3,456 shading units. The MI455X also has 1,024 TMUs versus the RX 7700 XT's 216 TMUs, but the RX 7700 XT has 96 ROPs while the MI455X has 0 ROPs.

Q: What is the release date for each product?

A: The MI455X has a release date of 2026-07-22, while the RX 7700 XT was released on 2023-09-05. The RX 7700 XT has a launch MSRP of 449 USD, while the MI455X has no launch MSRP listed.

Where Each One Wins

The RX 7700 XT wins in every category where the database contains measured performance. Its ten benchmark scores provide concrete evidence of graphics capability across multiple APIs, including DirectX 9, 10, 11, and 12, plus Vulkan and OpenCL. The MI455X has zero recorded benchmarks, so no measured performance advantage can be attributed to it. The RX 7700 XT is also the only one with display outputs, making it the sole option for any workload requiring visual output. Its API support for DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4 makes it usable in consumer software environments.

The MI455X wins on raw specification scale in several parameters, though none are benchmark-verified. Its 432 GB memory capacity and 23.3 TB/s bandwidth are orders of magnitude beyond the RX 7700 XT's 12 GB and 432.0 GB/s. The 2 nm process node is smaller than the 5 nm node of the RX 7700 XT, and the transistor count of 320,000 million versus 28,100 million indicates a far more complex chip. The FP32 throughput of 157.3 TFLOPS is approximately 4.5 times the RX 7700 XT's 35.17 TFLOPS. The MI455X's PCIe 6.0 x16 interface is newer than the PCIe 4.0 x16 of the RX 7700 XT.

The use-case split is clear from the data. The RX 7700 XT is the only part with measured graphics performance, and its nearest rivals in the database (RTX 5060 Mobile at 0.5% higher, RTX 4060 Mobile at 0.8% lower, RTX 2080 at 1.5% lower, RX 5700 at 1.7% higher) show it sits in a competitive mid-range band. The MI455X has no rivals listed and no benchmarks, so its specifications suggest a purpose-built accelerator for memory-bound or bandwidth-bound compute workloads, but the database cannot confirm any performance outcome. The MI455X requires a 2,700 W suggested PSU and has no display connectors, reinforcing its role as a compute module rather than a graphics card. The RX 7700 XT, with its 550 W suggested PSU, dual-slot design, and 267 mm length, fits a standard desktop environment. The MI455X's EAM Module slot width and lack of power connectors indicate a server or datacenter form factor.