AMD Instinct MI455X vs AMD Radeon 680M Comparison

FAQ

Q: What is the AMD Instinct MI455X, and what is its intended role?

A: The AMD Instinct MI455X is a data center accelerator built on the CDNA 5.0 architecture. It uses the MI450 256CU chip, is manufactured on a 2 nm process at TSMC, and features 432 GB of HBM4 memory with a 24576-bit bus. It has no display outputs and is designed for compute workloads, not graphics rendering.

Q: How does the AMD Radeon 680M compare in terms of architecture?

A: The AMD Radeon 680M is an integrated graphics processor (IGP) based on the RDNA 2.0 architecture, using the Rembrandt+ chip. It is built on a 6 nm process at TSMC and is part of the Navi II IGP generation for Rembrandt Mobile platforms. It supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4.

Q: What are the key memory specifications for each product?

A: The Instinct MI455X has 432 GB of HBM4 memory with a 24576-bit bus and 23.3 TB/s of bandwidth. The Radeon 680M uses System Shared memory, meaning its memory size, type, bus width, and bandwidth are all system dependent, with no dedicated VRAM.

Q: What is the difference in raw compute performance between the two?

A: The Instinct MI455X delivers 157.3 TFLOPS of FP32 performance and 157.3 TFLOPS of FP16 (1:1 ratio). The Radeon 680M delivers 3.379 TFLOPS of FP32 and 6.758 TFLOPS of FP16 (2:1 ratio). The MI455X is approximately 46.5 times higher in FP32 throughput based on these recorded figures.

Q: What do the benchmark scores show for the Radeon 680M?

A: The Radeon 680M has an average benchmark score of 15,270 across three tests: 3DMark Steel Nomad DX12 (378), Geekbench OpenCL (23,468), and Geekbench Vulkan (21,965). Its percentile versus all GPUs is 57. The Instinct MI455X has no recorded benchmarks and a percentile of 50.

Q: What are the power and interface differences?

A: The Instinct MI455X has a TDP of 2300 W, a suggested PSU of 2700 W, and uses a PCIe 6.0 x16 interface with an EAM Module slot width. The Radeon 680M has a TDP of 50 W, no suggested PSU, and uses PCIe 4.0 x8 with an IGP slot width.

The Verdict

The data presents two entirely distinct products with no overlapping use cases. The AMD Instinct MI455X is a high-end compute accelerator with 432 GB of HBM4 memory, 23.3 TB/s bandwidth, and 157.3 TFLOPS of FP32 performance. Its 2300 W power envelope and EAM Module form factor position it for data center and server workloads. The AMD Radeon 680M is an integrated GPU for mobile devices, with 768 shading units, 12 ray tracing cores, and a 50 W power draw.

For data center operators requiring massive memory capacity and extreme compute throughput, the Instinct MI455X is the clear choice. Its 24576-bit memory bus and 2 nm process node support large-scale AI training and inference tasks. For portable devices needing modest graphics performance with ray tracing support, the Radeon 680M fits that role, as it is marked Active in production status and has a successor listed as Navi III IGP.

The MI455X has no benchmarks recorded, so a direct performance comparison is impossible. However, its FP32 throughput of 157.3 TFLOPS versus the 680M's 3.379 TFLOPS indicates a massive compute gap. The 680M's nearest rivals are all discrete desktop GPUs: NVIDIA GeForce GTX 580 (avg score 15,283, delta -0.1%), NVIDIA GeForce RTX 2060 (avg score 15,290, delta -0.1%), NVIDIA GeForce RTX 3050 OEM (avg score 15,199, delta 0.5%), and AMD Radeon RX 7600 (avg score 15,171, delta 0.7%). These scores show the 680M sits within 0.7% of these desktop parts, which is notable for an integrated solution.

Head-to-Head Benchmarks

There are no recorded head-to-head benchmark entries between the AMD Instinct MI455X and the AMD Radeon 680M. The wins count is 0 for both products. The MI455X has no benchmarks listed in the database, while the 680M has three individual test scores.

The Radeon 680M's benchmark results show a Geekbench OpenCL score of 23,468 and a Geekbench Vulkan score of 21,965, indicating strong general compute performance for an IGP. Its 3DMark Steel Nomad DX12 score of 378 is more modest, reflecting the test's focus on modern gaming workloads. The average benchmark score of 15,270 places it at the 57th percentile among all GPUs.

Comparing the 680M to its nearest rivals, the data shows it is essentially tied with the NVIDIA GeForce GTX 580 and RTX 2060, both with a delta of -0.1%. It is slightly ahead of the RTX 3050 OEM by 0.5% and the AMD Radeon RX 7600 by 0.7%. This places the integrated 680M in the same performance class as several discrete desktop graphics cards from the previous generation.

For the Instinct MI455X, the absence of benchmark data means the database cannot confirm its real-world performance. The specification sheet indicates a device with 32768 shading units, 1024 texture mapping units, and a texture rate of 2,457.6 GTexel/s. Its pixel rate is recorded as 0 MPixel/s, which is consistent with a compute accelerator that has no display outputs.

Specification Differences

The AMD Instinct MI455X and AMD Radeon 680M differ in nearly every specification category.

Process and die: The MI455X uses a 2 nm process with 320,000 million transistors on a 2990 mm² die. The 680M uses a 6 nm process with 13,100 million transistors on a 208 mm² die. Transistor density is 107.0M per mm² for the MI455X versus 63.0M per mm² for the 680M.

Clock speeds: The MI455X has a base clock of 1000 MHz and a boost clock of 2400 MHz. The 680M has a base clock of 2000 MHz and a boost clock of 2200 MHz.

Memory: The MI455X has 432 GB of HBM4 memory with a 24576-bit bus and 23.3 TB/s bandwidth. The 680M uses System Shared memory with system dependent bandwidth.

Compute units: The MI455X has 32768 shading units, 1024 TMUs, and 0 ROPs. The 680M has 768 shading units, 48 TMUs, and 32 ROPs.

Ray tracing: The MI455X has no ray tracing cores listed. The 680M has 12 ray tracing cores.

Power: The MI455X has a TDP of 2300 W and a suggested PSU of 2700 W. The 680M has a TDP of 50 W and no suggested PSU.

Bus interface: The MI455X uses PCIe 6.0 x16. The 680M uses PCIe 4.0 x8.

Display outputs: The MI455X has no outputs. The 680M's outputs are portable device dependent.

API support: The MI455X has N/A for DirectX, OpenGL, and Vulkan. The 680M supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4.

Architecture Differences

The architectural divide between these two AMD products is substantial.

The Instinct MI455X uses the CDNA 5.0 architecture, which is designed specifically for compute acceleration. Its 256 compute unit chip (MI450 256CU) drives 32768 shading units with a 1:1 FP16 to FP32 ratio, meaning both precision levels deliver 157.3 TFLOPS. The memory subsystem uses HBM4 across a 24576-bit bus, allowing 23.3 TB/s of bandwidth. The architecture does not include traditional rasterization units (0 ROPs) or display outputs, confirming its server-focused design. The pixel rate of 0 MPixel/s further indicates the absence of a graphics pipeline.

The Radeon 680M uses the RDNA 2.0 architecture, which is a unified graphics and compute design. Its 768 shading units operate with a 2:1 FP16 to FP32 ratio, producing 6.758 TFLOPS FP16 and 3.379 TFLOPS FP32. The 12 ray tracing cores enable hardware-accelerated ray tracing, a feature absent from the MI455X. The 680M has 32 ROPs and a pixel rate of 70.40 GPixel/s, supporting its role as a graphics processor. Its system shared memory architecture relies on the host system's memory bandwidth.

The process technology difference is significant: 2 nm versus 6 nm. The MI455X packs 320,000 million transistors into a 2990 mm² die, while the 680M fits 13,100 million transistors into 208 mm². The MI455X is a discrete accelerator module with an EAM slot width, while the 680M is an IGP integrated into a mobile processor.

The MI455X has a base clock of 1000 MHz and boost of 2400 MHz, despite its much larger transistor count. The 680M has a narrower clock range of 2000 MHz to 2200 MHz. The MI455X's memory clock is 1900 MHz with 7.6 Gbps effective speed, while the 680M's memory clock depends entirely on the system.

Where Each One Wins

Based on the recorded data, the AMD Instinct MI455X wins in every absolute compute metric. Its 157.3 TFLOPS FP32 performance dwarfs the 3.379 TFLOPS of the 680M. The 432 GB HBM4 memory capacity with 23.3 TB/s bandwidth is orders of magnitude beyond the system shared memory of the 680M. The 2 nm process node and 320,000 million transistors enable a texture rate of 2,457.6 GTexel/s, compared to 105.6 GTexel/s for the 680M.

The AMD Radeon 680M wins in areas related to graphics output and power efficiency. It has 32 ROPs and a pixel rate of 70.40 GPixel/s, while the MI455X has 0 ROPs and 0 MPixel/s. The 680M supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4, while the MI455X has no graphics API support. The 680M's 50 W TDP is 46 times lower than the MI455X's 2300 W.

The 680M also has a production status of Active, meaning it is currently available, while the MI455X has no production status listed. The 680M has a predecessor (Vega II IGP) and successor (Navi III IGP), indicating an established product line. The MI455X lists Radeon Instinct as its predecessor and no successor.

For benchmark data, the Radeon 680M has three recorded scores, including a Geekbench OpenCL result of 23,468. The Instinct MI455X has zero recorded benchmarks. The nearest rival data for the 680M shows it performs comparably to the NVIDIA GeForce RTX 2060 and GTX 580, both within 0.1% of its average score. This suggests the integrated 680M can handle workloads typically assigned to discrete desktop GPUs from previous generations.

The Instinct MI455X's launch date is set for 2026-07-22, while the 680M launched on 2023-01-02. The MI455X is expected to be a next-generation compute accelerator, while the 680M is an established mobile graphics solution. Each product wins in its respective domain: the MI455X for raw compute density and memory bandwidth, the 680M for integrated graphics capability and low power operation.