AMD Radeon Instinct MI25 vs NVIDIA Tesla P40 Comparison

AMD Radeon Instinct MI25 and NVIDIA Tesla P40 are both end-of-life data center accelerators from the 2016-2017 era, but they represent fundamentally different design philosophies from their respective manufacturers. The MI25 is AMD's high-compute-density answer built on the Vega architecture, while the P40 is NVIDIA's high-memory-capacity workhorse based on Pascal. Benchmark data shows the AMD card holds a significant edge in raw compute workloads, while the NVIDIA card offers substantially more memory capacity. This analysis breaks down the performance, architectural, and specification differences between these two legacy accelerators.

Head-to-Head Benchmarks

The only direct benchmark comparison available is the Geekbench OpenCL test, and the results clearly favor the AMD Radeon Instinct MI25. In this compute-heavy workload, the MI25 scores 68,562 points against the Tesla P40's 62,017 points, giving AMD a 10.6% performance advantage. This is a decisive margin in a benchmark that stresses raw parallel compute throughput, which aligns with the MI25's higher FP32 and FP16 performance figures.

Looking at the broader competitive landscape, the MI25's average benchmark score of 68,562 places it in the 90th percentile of all GPUs, while the P40's average of 65,095 sits at the 89th percentile. The MI25's nearest rivals include the Intel Arc A770 (68,809, just 0.4% ahead), the NVIDIA CMP 90HX (69,000, 0.6% ahead), and the AMD Radeon Pro WX 8200 (69,870, 1.9% ahead). This indicates the MI25 is competitive with much newer hardware despite its age. The P40, by contrast, sits 1.4% ahead of the AMD Radeon Pro WX 9100 (64,212) and 2% ahead of both the NVIDIA CMP 30HX (63,842) and the AMD Radeon RX 9060 XT LP (63,830), but trails the AMD Radeon VII (66,004) by 1.4%.

In the head-to-head matchup, the MI25 wins the only available benchmark, taking a 10.6% lead in Geekbench OpenCL. This performance gap is substantial and reflects the MI25's architectural advantages in compute throughput. The MI25's FP32 rating of 12.29 TFLOPS exceeds the P40's 11.76 TFLOPS, and in FP16 workloads the difference is even more dramatic — the MI25 delivers 24.58 TFLOPS with a 2:1 ratio, while the P40 manages only 183.7 GFLOPS with a heavily reduced 1:64 ratio. This makes the MI25 over 130 times faster in half-precision compute, a critical differentiator for AI inference workloads that rely on FP16 arithmetic.

However, the P40 fights back in memory capacity, offering 24 GB of GDDR5 memory versus the MI25's 16 GB of HBM2. While the MI25 has higher memory bandwidth at 436.2 GB/s compared to the P40's 347.1 GB/s, the P40's larger capacity allows it to hold bigger datasets and models in memory, which can be a deciding factor in workloads that are memory-capacity-bound rather than compute-bound.

Architecture Differences

The architectural divide between these two cards is stark. The AMD Radeon Instinct MI25 is built on the Vega 10 chip using GCN 5.0 architecture, manufactured on GlobalFoundries' 14 nm process. It packs 12,500 million transistors into a 495 mm² die, yielding a transistor density of 25.3 million per square millimeter. The NVIDIA Tesla P40, in contrast, uses the GP102 chip with Pascal architecture, fabricated by TSMC on a 16 nm process. It contains 11,800 million transistors on a 471 mm² die, with a slightly lower transistor density of 25.1 million per square millimeter.

The compute unit configurations differ significantly. The MI25 features 4,096 shading units, 256 texture mapping units, and 64 render output units. The P40 has 3,840 shading units, 240 TMUs, and 96 ROPs. This gives the MI25 more shader and texture processing hardware, while the P40 has more ROPs, which explains its higher pixel rate of 147.0 GPixel/s versus the MI25's 96.00 GPixel/s. The texture rates are closer, with the MI25 at 384.0 GTexel/s and the P40 at 367.4 GTexel/s.

Clock speeds tell an interesting story. The MI25 runs at a 1400 MHz base clock and 1500 MHz boost, while the P40 has a lower 1303 MHz base but a higher 1531 MHz boost. The memory clocks are dramatically different: the MI25's HBM2 runs at 852 MHz with 1704 Mbps effective, while the P40's GDDR5 runs at 1808 MHz with 7.2 Gbps effective. Despite the P40's much higher memory clock, the MI25's 2048-bit memory bus versus the P40's 384-bit bus results in the MI25 having superior bandwidth.

Power and cooling requirements differ as well. The MI25 draws 300 W TDP and requires a 700 W suggested PSU with 2x 8-pin power connectors, while the P40 is more power-efficient at 250 W TDP with a 600 W suggested PSU and a single 8-pin EPS connector. Both cards are dual-slot designs with identical physical dimensions — 267 mm in length and 111 mm in height — and neither has display outputs.

API support shows some divergence. Both support DirectX 12 (12_1) and OpenGL 4.6, but the P40 supports Vulkan 1.4 while the MI25 is limited to Vulkan 1.3. Neither card has ray tracing or tensor cores.

The Verdict

The data clearly indicates that the AMD Radeon Instinct MI25 is the superior choice for compute-heavy workloads. It wins the Geekbench OpenCL benchmark by 10.6%, offers higher FP32 performance (12.29 TFLOPS vs. 11.76 TFLOPS), and delivers an overwhelmingly better FP16 capability (24.58 TFLOPS vs. 183.7 GFLOPS). For AI inference, scientific computing, or any workload that leverages half-precision arithmetic, the MI25 is categorically the better performer.

The NVIDIA Tesla P40's primary advantage is memory capacity. With 24 GB versus 16 GB, the P40 can accommodate larger models and datasets without spilling to system memory. This makes it the better choice for workloads that are memory-capacity-bound, such as certain large-scale data analytics or inference tasks with very large batch sizes. However, the MI25's higher bandwidth (436.2 GB/s vs. 347.1 GB/s) partially compensates for its smaller capacity in bandwidth-sensitive scenarios.

The P40 also consumes less power — 250 W versus 300 W — and has a lower suggested PSU requirement of 600 W versus 700 W. For dense server deployments where power density is a concern, the P40's lower TDP could be a meaningful advantage, but the performance differential favors the MI25 in most compute scenarios.

The MI25's 90th percentile ranking versus the P40's 89th percentile reinforces its overall performance edge. The MI25 also sits closer to its nearest rivals in the benchmark hierarchy, with the closest competitor being just 0.4% ahead, while the P40's closest rival trails by 1.4%. Given the MI25's substantial FP16 advantage and higher overall compute throughput, it is the recommended choice for users prioritizing raw performance. The P40 remains viable only when its larger memory capacity is the deciding factor.

Specification Differences

| Specification | AMD Radeon Instinct MI25 | NVIDIA Tesla P40 |

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

| Chip | Vega 10 | GP102 |

| Architecture | GCN 5.0 | Pascal |

| Process Node | 14 nm | 16 nm |

| Foundry | GlobalFoundries | TSMC |

| Transistors | 12,500 million | 11,800 million |

| Die Size | 495 mm² | 471 mm² |

| Transistor Density | 25.3M / mm² | 25.1M / mm² |

| Base Clock | 1400 MHz | 1303 MHz |

| Boost Clock | 1500 MHz | 1531 MHz |

| Memory Clock | 852 MHz / 1704 Mbps effective | 1808 MHz / 7.2 Gbps effective |

| Memory Size | 16 GB | 24 GB |

| Memory Type | HBM2 | GDDR5 |

| Memory Bus Width | 2048 bit | 384 bit |

| Memory Bandwidth | 436.2 GB/s | 347.1 GB/s |

| Shading Units | 4096 | 3840 |

| TMUs | 256 | 240 |

| ROPs | 64 | 96 |

| Pixel Rate | 96.00 GPixel/s | 147.0 GPixel/s |

| Texture Rate | 384.0 GTexel/s | 367.4 GTexel/s |

| FP32 | 12.29 TFLOPS | 11.76 TFLOPS |

| FP16 | 24.58 TFLOPS (2:1) | 183.7 GFLOPS (1:64) |

| TDP | 300 W | 250 W |

| Power Connectors | 2x 8-pin | 8-pin EPS |

| Suggested PSU | 700 W | 600 W |

| Vulkan API | 1.3 | 1.4 |

| Release Date | 2017-06-26 | 2016-09-12 |

| Predecessor | FirePro Data Center | Tesla Maxwell |

| Successor | None | Tesla Volta |

| Launch MSRP | N/A | 5,699 USD |

FAQ

Q: Which card is faster in Geekbench OpenCL?

A: The AMD Radeon Instinct MI25 scores 68,562 compared to the NVIDIA Tesla P40's 62,017, giving the MI25 a 10.6% performance advantage in this benchmark.

Q: How do the FP16 compute capabilities compare?

A: The MI25 delivers 24.58 TFLOPS FP16 performance with a 2:1 ratio, while the P40 manages only 183.7 GFLOPS with a 1:64 ratio, making the MI25 overwhelmingly faster in half-precision workloads.

Q: Which card has more memory?

A: The NVIDIA Tesla P40 has 24 GB of GDDR5 memory, which is 50% more than the AMD Radeon Instinct MI25's 16 GB of HBM2 memory.

Q: What is the memory bandwidth difference?

A: The MI25 offers 436.2 GB/s of memory bandwidth, which is higher than the P40's 347.1 GB/s, despite the P40's larger capacity.

Q: What is the launch MSRP of the Tesla P40?

A: The NVIDIA Tesla P40 had a launch MSRP of 5,699 USD. The MI25 has no listed launch MSRP in the data.

Q: Which card has better Vulkan support?

A: The NVIDIA Tesla P40 supports Vulkan 1.4, while the AMD Radeon Instinct MI25 is limited to Vulkan 1.3 support.