AMD Instinct MI455X vs AMD Radeon 820M Comparison

The AMD Instinct MI455X and the AMD Radeon 820M occupy opposite extremes of the hardware spectrum. The MI455X is a 2 nm, 2300 W compute module built for data centers, while the 820M is a 15 W integrated graphics processor for mobile devices. The database shows no shared benchmark results between these two parts, which is expected given their entirely different target environments. The MI455X has an average benchmark score of zero, and the 820M also has an average benchmark score of zero. Both sit at the 50th percentile against all GPUs in the database, though this percentile reflects the absence of recorded measurements rather than comparable performance.

Head-to-Head Benchmarks

The recorded data contains no direct head-to-head benchmark runs for the AMD Instinct MI455X versus the AMD Radeon 820M. The head-to-head comparison fields are empty, and neither part has any individual benchmark entries in the database. This means there are no exact scores, no delta percentages, and no win counts to report. The MI455X has zero wins in the comparison, and the 820M also has zero wins.

Without measured results, the analysis must rely on the theoretical specifications recorded for each chip. The MI455X delivers 157.3 TFLOPS of FP32 compute, while the 820M delivers 716.8 GFLOPS. The difference is substantial. The MI455X also reaches a texture rate of 2,457.6 GTexel/s compared to 22.40 GTexel/s for the 820M. Pixel output goes the other way on paper only because the MI455X has no display outputs and a pixel rate of 0 MPixel/s, while the 820M has a pixel rate of 11.20 GPixel/s.

The absence of recorded benchmarks means these numbers are not validated by any workload. The database lists the MI455X with a boost clock of 2400 MHz and a base clock of 1000 MHz. The 820M boosts to 2800 MHz from a 400 MHz base. Clock speed alone does not tell the full story, because the two architectures handle instructions very differently.

Where Each One Wins

Based on the recorded specifications, the MI455X wins decisively in raw compute throughput. Its FP32 rating of 157.3 TFLOPS dwarfs the 820M's 716.8 GFLOPS. The texture rate of 2,457.6 GTexel/s versus 22.40 GTexel/s reinforces that the MI455X is built for massive parallel workloads. The MI455X also has 32,768 shading units, 1,024 texture mapping units, and a 24576-bit memory bus feeding 432 GB of HBM4 memory with 23.3 TB/s of bandwidth. The 820M has 128 shading units, 8 TMUs, and system-shared memory with system-dependent bandwidth.

The 820M wins in areas related to graphics output and integration. It has 4 ROPs, a pixel rate of 11.20 GPixel/s, and supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. The MI455X has no display outputs and lists all its API support as N/A. The 820M also fits into a 15 W power envelope and uses a PCIe 4.0 x8 interface, while the MI455X requires a 2300 W TDP and a suggested power supply of 2700 W. The 820M is an active production product, while the MI455X has no production status listed.

For mobile or integrated graphics tasks, the 820M is the only one of the two that can render to a screen. The MI455X is an accelerator module with no video outputs, so it cannot drive a display at all. The data indicates a clear functional split: the MI455X for compute acceleration, the 820M for graphics rendering in portable systems.

Architecture Differences

The MI455X uses the CDNA 5.0 architecture, while the 820M uses RDNA 3.5. These are different design families from AMD. CDNA 5.0 is listed under the Instinct (MIx) generation, and RDNA 3.5 is under the Navi III IGP (Strix Point Mobile) generation. The MI455X chip is labeled MI450 256CU. The 820M chip is labeled Krackan Point 2.

Process technology differs. The MI455X is built on a 2 nm node at TSMC, with 320,000 million transistors on a 2990 mm² die. That results in a transistor density of 107.0M per mm². The 820M is built on a 4 nm node, also at TSMC, but its transistor count and die size are listed as unknown.

Memory architecture is completely different. The MI455X uses 432 GB of HBM4 on a 24576-bit bus with 23.3 TB/s bandwidth. The 820M uses system-shared memory with a system-shared bus width and system-dependent bandwidth. The MI455X memory clock is 1900 MHz, which the database notes as 7.6 Gbps effective. The 820M memory clock is listed as system shared.

Compute resources diverge sharply. The MI455X has 32,768 shading units, 1,024 TMUs, and no ROPs. The 820M has 128 shading units, 8 TMUs, and 4 ROPs. The MI455X does not list ray tracing cores, while the 820M lists 2 ray tracing cores. Neither part lists tensor cores in the database.

Power and physical design also differ. The MI455X is an EAM Module with no power connectors and a 2300 W TDP. The 820M is an IGP with no power connectors and a 15 W TDP. The MI455X uses PCIe 6.0 x16, while the 820M uses PCIe 4.0 x8. The MI455X has no display outputs, and the 820M has display outputs described as portable device dependent.

API support is a major split. The MI455X lists DirectX, OpenGL, and Vulkan all as N/A. The 820M supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. FP16 performance matches FP32 at a 1:1 ratio on both parts, with the MI455X at 157.3 TFLOPS and the 820M at 716.8 GFLOPS.

FAQ

Q: Which GPU has higher FP32 compute performance?

A: The AMD Instinct MI455X delivers 157.3 TFLOPS of FP32 performance, while the AMD Radeon 820M delivers 716.8 GFLOPS. The MI455X has the higher raw compute throughput.

Q: Can the AMD Instinct MI455X output video to a display?

A: No. The MI455X lists display outputs as no outputs and has a pixel rate of 0 MPixel/s. The AMD Radeon 820M has display outputs listed as portable device dependent and a pixel rate of 11.20 GPixel/s.

Q: What memory configurations do these two GPUs use?

A: The MI455X uses 432 GB of HBM4 memory on a 24576-bit bus with 23.3 TB/s of bandwidth. The 820M uses system-shared memory with system-shared bus width and system-dependent bandwidth.

Q: What is the power consumption difference?

A: The MI455X has a TDP of 2300 W and a suggested power supply of 2700 W. The 820M has a TDP of 15 W and no suggested power supply listed.

Q: Which GPU supports modern graphics APIs?

A: The AMD Radeon 820M supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. The AMD Instinct MI455X lists all its graphics APIs as N/A.

Q: What process nodes are used for each chip?

A: The MI455X is fabricated on a 2 nm process at TSMC with 320,000 million transistors on a 2990 mm² die. The 820M is fabricated on a 4 nm process at TSMC, with transistor count and die size listed as unknown.

The Verdict

The data in the database points to two different products for two different jobs. The AMD Instinct MI455X is a compute accelerator with 157.3 TFLOPS of FP32 throughput, 432 GB of HBM4 memory, and 23.3 TB/s of bandwidth. It has no display outputs and no graphics API support. Its 2300 W TDP and 2700 W suggested power supply place it firmly in a server or data center context.

The AMD Radeon 820M is an integrated processor for mobile systems. It delivers 716.8 GFLOPS of FP32 compute, supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4, and has 2 ray tracing cores. Its 15 W TDP makes it suitable for portable devices, and its display outputs are portable device dependent.

The recorded data shows no benchmark scores for either part, so performance claims cannot be validated by workload results. The specification sheet, however, indicates that the MI455X is built for massive parallel compute with a 24576-bit memory bus and 32,768 shading units. The 820M is built for graphics rendering with 4 ROPs and a pixel rate of 11.20 GPixel/s. The choice between them depends entirely on the use case. For compute acceleration with no display output requirement, the MI455X is the only option that fits. For integrated graphics in a mobile device, the 820M is the only option that fits.

Specification Differences

The two GPUs differ in nearly every recorded specification field. The MI455X uses the CDNA 5.0 architecture, while the 820M uses RDNA 3.5. The MI455X generation is Instinct (MIx), and the 820M generation is Navi III IGP (Strix Point Mobile). The MI455X chip is MI450 256CU, and the 820M chip is Krackan Point 2.

Process node: 2 nm for the MI455X versus 4 nm for the 820M, both at TSMC. The MI455X has 320,000 million transistors on a 2990 mm² die with a density of 107.0M per mm². The 820M has unknown transistor count and die size.

Base clock: 1000 MHz for the MI455X versus 400 MHz for the 820M. Boost clock: 2400 MHz for the MI455X versus 2800 MHz for the 820M. Memory clock: 1900 MHz (7.6 Gbps effective) for the MI455X versus system shared for the 820M.

Memory size: 432 GB for the MI455X versus system shared for the 820M. Memory type: HBM4 versus system shared. Bus width: 24576 bit versus system shared. Bandwidth: 23.3 TB/s versus system dependent.

Shading units: 32,768 versus 128. TMUs: 1,024 versus 8. ROPs: 0 versus 4. Ray tracing cores: not listed for the MI455X versus 2 for the 820M. Pixel rate: 0 MPixel/s versus 11.20 GPixel/s. Texture rate: 2,457.6 GTexel/s versus 22.40 GTexel/s. FP32: 157.3 TFLOPS versus 716.8 GFLOPS. FP16: 157.3 TFLOPS (1:1) versus 716.8 GFLOPS (1:1).

TDP: 2300 W versus 15 W. Slot width: EAM Module versus IGP. Power connectors: none for both. Suggested PSU: 2700 W for the MI455X, none for the 820M. Bus interface: PCIe 6.0 x16 versus PCIe 4.0 x8. Display outputs: no outputs versus portable device dependent. DirectX: N/A versus 12 Ultimate (12_2). OpenGL: N/A versus 4.6. Vulkan: N/A versus 1.4. Release date: 2026-07-22 versus 2025-02-28. Predecessor: Radeon Instinct versus Navi II IGP. Production status: not listed versus active.