AMD Radeon Instinct MI25 vs AMD Radeon Pro Vega 56 Comparison

The AMD Radeon Instinct MI25 and AMD Radeon Pro Vega 56 are both built on the same Vega 10 silicon, but they are configured for very different jobs. The benchmark data shows a clear, though not overwhelming, performance gap in favor of the Instinct MI25, alongside significant trade-offs in power, memory, and physical design. This analysis compares the two directly using only the provided specifications and benchmark results.

Head-to-Head Benchmarks

The only direct benchmark comparison available is the Geekbench OpenCL test. In this test, the AMD Radeon Instinct MI25 scores 68,562 points, while the AMD Radeon Pro Vega 56 scores 61,930 points. This gives the Instinct MI25 a decisive 10.7% lead over the Pro Vega 56 in raw compute throughput.

This advantage is consistent with the broader performance context. The Instinct MI25's average benchmark score is 68,562, placing it in the 90th percentile of all GPUs. Its nearest rivals include the Intel Arc A770 (average score 68,809, a delta of -0.4%) and the NVIDIA Quadro P6000 (average score 69,986, a delta of -2%). The Instinct MI25 is effectively neck-and-neck with the Arc A770 and only 2% behind the Quadro P6000, which shows it is a very competitive compute part despite its age.

The Radeon Pro Vega 56, in contrast, has an average benchmark score of 63,693 across its tested APIs (OpenCL, Metal, and Vulkan). This places it in the 89th percentile, just one point lower than the Instinct MI25. Its nearest rival is the AMD Radeon RX 7600M (average score 63,775, a delta of -0.1%), indicating it is essentially matched by that mobile GPU. The Pro Vega 56's single OpenCL score of 61,930 is its lowest result; its Vulkan score of 66,004 and Metal score of 63,145 are higher, but still below the Instinct MI25's OpenCL result.

The data indicates that in the most common cross-platform compute test, the Instinct MI25 is the faster card. The 10.7% delta in OpenCL is substantial enough to matter for tasks that rely heavily on that API, such as many scientific and data-center workloads. However, the Pro Vega 56 is not far behind, and its performance in Vulkan suggests it is not a slouch in all APIs.

Architecture Differences

Both GPUs are built on the same fundamental architecture: GCN 5.0 on a 14 nm process at GlobalFoundries. They share the same die size of 495 mm² and contain 12,500 million transistors, resulting in a transistor density of 25.3M / mm². The core configuration, however, is where they diverge.

The AMD Radeon Instinct MI25 is the more fully-featured chip. It has 4,096 shading units, 256 texture mapping units (TMUs), and 64 render output units (ROPs). In contrast, the AMD Radeon Pro Vega 56 has fewer of these resources: 3,584 shading units, 224 TMUs, and the same 64 ROPs. This difference of 512 shading units and 32 TMUs explains the raw compute gap between the two.

Clock speeds further widen the performance divide. The Instinct MI25 runs at a base clock of 1400 MHz and a boost clock of 1500 MHz. The Pro Vega 56 is significantly slower in this regard, with a base clock of 1138 MHz and a boost clock of 1250 MHz. The higher clock speeds and the larger shader array on the Instinct MI25 directly translate to its superior throughput rates: the Instinct MI25 achieves 12.29 TFLOPS FP32 and 24.58 TFLOPS FP16 (2:1), while the Pro Vega 56 delivers only 8.960 TFLOPS FP32 and 17.92 TFLOPS FP16 (2:1).

Memory is another area of significant difference. Both use HBM2 memory on a 2048-bit bus, but the Instinct MI25 has 16 GB of it, double the 8 GB found on the Pro Vega 56. Memory clocks also differ, with the Instinct MI25 running at 852 MHz (1704 Mbps effective) versus 786 MHz (1572 Mbps effective) on the Pro Vega 56. This results in a memory bandwidth of 436.2 GB/s for the Instinct MI25, compared to 402.4 GB/s for the Pro Vega 56. The higher capacity and bandwidth of the Instinct MI25 make it better suited for large datasets that exceed 8 GB.

Where Each One Wins

The AMD Radeon Instinct MI25 wins in every category where the two can be directly compared. It is faster in raw compute, has more memory, and has higher bandwidth. Its 10.7% lead in OpenCL and its 16 GB frame buffer make it the clear choice for compute-heavy applications, particularly those that can leverage large datasets or benefit from FP16 throughput. The data shows it is a dedicated accelerator, with no display outputs, reinforcing its role as a server or data-center compute card.

The AMD Radeon Pro Vega 56, despite losing the direct comparison, has its own strengths. Its most notable advantage is its physical form factor. It is listed as an "IGP" (integrated graphics processor) with no power connectors and a 210 W TDP. This is in stark contrast to the Instinct MI25, which is a dual-slot card requiring 2x 8-pin power connectors and a 300 W TDP. The Pro Vega 56 also has display outputs (1x HDMI 2.0b and 3x DisplayPort 1.4a), whereas the Instinct MI25 has none. This makes the Pro Vega 56 a viable option for a workstation where compute and display are needed from the same card, without requiring a separate GPU for output.

Furthermore, in the Vulkan API, the Pro Vega 56 scores 66,004, which is closer to the Instinct MI25's OpenCL result. While this is not a direct comparison, it suggests that in certain API-specific workloads, the Pro Vega 56 may perform relatively better than its OpenCL score suggests. The Pro Vega 56's lower power draw and integrated design also make it easier to deploy in systems with less robust power delivery. For a user who needs a single-card solution for a Mac Pro or a compact workstation, the Pro Vega 56 is the only option of the two.

The Verdict

The verdict is straightforward based on the data. If raw compute performance is the sole priority, the AMD Radeon Instinct MI25 is the superior card. It is 10.7% faster in OpenCL, has double the memory capacity (16 GB vs 8 GB), higher memory bandwidth (436.2 GB/s vs 402.4 GB/s), and significantly higher pixel and texture rates (96.00 GPixel/s vs 80.00 GPixel/s, and 384.0 GTexel/s vs 280.0 GTexel/s, respectively). Its 90th percentile standing among all GPUs, compared to the Pro Vega 56's 89th percentile, confirms its higher tier of performance. Anyone building a compute node for machine learning, scientific simulation, or rendering tasks that can use the full 16 GB buffer should choose the Instinct MI25.

However, the Pro Vega 56 is not without merit. Its 210 W TDP versus 300 W for the Instinct MI25 makes it a far more power-efficient option. Its integrated form factor and lack of external power connectors mean it can fit into systems where a dual-slot, power-hungry card like the Instinct MI25 cannot. The presence of display outputs is a critical differentiator. For a professional who needs a single card that can drive monitors and accelerate compute workloads, the Pro Vega 56 is the only choice. The Instinct MI25 cannot output a display signal at all.

Strictly from the data, the choice depends on the system's role. For a dedicated compute server, pick the Instinct MI25. For a workstation that needs a combined compute and display solution with lower power requirements, pick the Pro Vega 56. The performance gap is real but not enormous, and the physical and power constraints may be decisive for many users.

FAQ

Q: Which GPU is faster in the OpenCL benchmark?

A: The AMD Radeon Instinct MI25 is faster, scoring 68,562 compared to the AMD Radeon Pro Vega 56's 61,930, a 10.7% difference.

Q: How much memory does each card have?

A: The AMD Radeon Instinct MI25 has 16 GB of HBM2 memory, while the AMD Radeon Pro Vega 56 has 8 GB of HBM2 memory.

Q: Can both cards be used to output video to a display?

A: No. The AMD Radeon Instinct MI25 has no display outputs, while the AMD Radeon Pro Vega 56 has 1x HDMI 2.0b and 3x DisplayPort 1.4a outputs.

Q: What is the difference in power consumption?

A: The AMD Radeon Instinct MI25 has a 300 W TDP and requires 2x 8-pin power connectors, whereas the AMD Radeon Pro Vega 56 has a 210 W TDP and requires no power connectors.

Q: Are these GPUs based on the same architecture?

A: Yes, both are based on the GCN 5.0 architecture using the Vega 10 chip, manufactured on a 14 nm process at GlobalFoundries.

Q: Which card has better performance relative to other GPUs on the market?

A: The AMD Radeon Instinct MI25 is in the 90th percentile of all GPUs, while the AMD Radeon Pro Vega 56 is in the 89th percentile. Their nearest rivals include the Intel Arc A770 and NVIDIA Quadro P6000 for the Instinct, and the AMD Radeon RX 7600M for the Pro Vega.

Specification Differences

| Specification | AMD Radeon Instinct MI25 | AMD Radeon Pro Vega 56 |

| :--- | :--- | :--- |

| Base Clock | 1400 MHz | 1138 MHz |

| Boost Clock | 1500 MHz | 1250 MHz |

| Memory Size | 16 GB | 8 GB |

| Memory Clock | 852 MHz (1704 Mbps effective) | 786 MHz (1572 Mbps effective) |

| Memory Bandwidth | 436.2 GB/s | 402.4 GB/s |

| Shading Units | 4096 | 3584 |

| TMUs | 256 | 224 |

| Pixel Rate | 96.00 GPixel/s | 80.00 GPixel/s |

| Texture Rate | 384.0 GTexel/s | 280.0 GTexel/s |

| FP32 Performance | 12.29 TFLOPS | 8.960 TFLOPS |

| FP16 Performance | 24.58 TFLOPS (2:1) | 17.92 TFLOPS (2:1) |

| TDP | 300 W | 210 W |

| Slot Width | Dual-slot | IGP |

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

| Suggested PSU | 700 W | None |

| Display Outputs | No outputs | 1x HDMI 2.0b, 3x DisplayPort 1.4a |

| Release Date | 2017-06-26 | 2017-08-13 |