AMD Instinct MI100 vs NVIDIA A100 PCIe 80 GB Comparison

The NVIDIA A100 PCIe 80 GB and AMD Instinct MI100 are both end-of-life server accelerators built on TSMC's 7 nm process, but they represent fundamentally different architectural philosophies. The benchmark data shows a decisive performance gap, yet the specifications reveal why each card targets distinct workloads. Below is a quantitative breakdown of their relative standing, drawing exclusively from the provided benchmark results and hardware specifications.

Head-to-Head Benchmarks

The Geekbench OpenCL score is the sole direct performance comparison available. In this test, the NVIDIA A100 PCIe 80 GB achieves a score of 207,124, while the AMD Instinct MI100 scores 139,035. This yields a 49% advantage for the A100, making it the clear winner in the only head-to-head benchmark recorded.

The A100's score places it in the 99th percentile of all GPUs, whereas the MI100 sits in the 96th percentile. This three-percentile gap translates into meaningful real-world positioning: the A100 outperforms its nearest rival, the NVIDIA RTX 6000D (average score 195,964), by 5.7%. It also beats the NVIDIA Tesla V100S PCIe 32 GB (194,415) by 6.5%. However, the A100 trails two competitors: the AMD Radeon PRO W7900D (219,827) by 5.8% and the NVIDIA PG506-232 (225,124) by 8%.

The MI100's benchmark score of 139,035 places it in a much tighter competitive cluster. Its nearest rival, the NVIDIA Tesla V100 PCIe 16 GB (138,063), is only 0.7% behind. The NVIDIA Tesla V100 SXM2 32 GB (137,731) is 0.9% behind, while the AMD Radeon PRO V620 (136,472) trails by 1.9%. The AMD Radeon Pro W6800X Duo (135,774) is the closest competitor at 2.4% behind. This suggests the MI100 is competitive with the previous-generation V100 series, but the A100 operates in a different performance tier entirely.

The 49% delta between the two cards is substantial. For context, this is nearly ten times larger than the gap between the MI100 and its closest rival. The data indicates that the A100 delivers roughly 1.5 times the OpenCL throughput of the MI100, a difference that would dominate any compute workload sensitive to raw GPU performance.

Architecture Differences

The architectural divide between these two accelerators is stark. The NVIDIA A100 PCIe 80 GB uses the GA100 chip based on the Ampere architecture, while the AMD Instinct MI100 uses the Arcturus chip based on CDNA 1.0. Both are fabricated on TSMC's 7 nm process, but the transistor counts differ dramatically: the A100 contains 54,200 million transistors on an 826 mm² die, yielding a density of 65.6 million transistors per mm². The MI100 has 25,600 million transistors on a 750 mm² die, with a density of 34.1 million per mm².

This transistor advantage translates directly into compute resources. The A100 has 6,912 shading units, 432 texture mapping units, and 160 raster output units. The MI100 counters with 7,680 shading units, 480 TMUs, but only 64 ROPs. The MI100's higher shading unit count gives it a theoretical FP32 output of 23.07 TFLOPS, surpassing the A100's 19.49 TFLOPS. However, the A100's FP16 performance is far higher: 77.97 TFLOPS (at a 4:1 ratio) versus the MI100's 46.14 TFLOPS (at a 2:1 ratio).

The A100 also integrates 432 tensor cores, a feature entirely absent from the MI100. This is a critical differentiator for deep learning workloads that rely on tensor operations. The MI100 has no equivalent hardware, meaning any matrix-multiplication-heavy task will rely on its general-purpose FP32 or FP16 units.

Memory configurations diverge significantly. The A100 ships with 80 GB of HBM2e memory on a 5120-bit bus, delivering 1.94 TB/s of bandwidth. The MI100 has 32 GB of HBM2 on a 4096-bit bus, providing 1.23 TB/s. The A100's memory advantage is twofold: 2.5 times the capacity and 58% more bandwidth. The A100's memory clock runs at 1512 MHz (3 Gbps effective), while the MI100's runs at 1200 MHz (2.4 Gbps effective).

Pixel and texture throughput further highlight the differences. The A100 achieves 225.6 GPixel/s pixel rate and 609.1 GTexel/s texture rate. The MI100 manages only 96.13 GPixel/s and 721.0 GTexel/s, respectively. The MI100's higher texture rate is a result of its additional TMUs, but its pixel rate is less than half the A100's due to the significantly lower ROP count.

Neither card features ray tracing cores, and both have no display outputs. The A100 has no DirectX, OpenGL, or Vulkan API entries, whereas the MI100 explicitly lists all three as "N/A." Both use a PCIe 4.0 x16 interface.

The Verdict

The data strongly favors the NVIDIA A100 PCIe 80 GB for any workload measured by Geekbench OpenCL. Its 49% higher score and 99th percentile ranking versus the MI100's 96th percentile make it the superior choice for general compute throughput. The A100's massive memory capacity (80 GB vs 32 GB) and higher bandwidth (1.94 TB/s vs 1.23 TB/s) also provide clear advantages for large datasets and memory-bound applications.

The MI100 does have one theoretical edge: its FP32 throughput of 23.07 TFLOPS exceeds the A100's 19.49 TFLOPS. This could benefit workloads that rely heavily on single-precision floating-point math without tensor core acceleration. However, the benchmark data does not reflect this advantage in the OpenCL score, suggesting real-world performance is dominated by other factors.

For deep learning and AI inference, the A100's 432 tensor cores and superior FP16 performance (77.97 TFLOPS vs 46.14 TFLOPS) make it the obvious pick. The MI100 lacks tensor cores entirely, ceding this entire workload category. For scientific computing that primarily uses FP32, the MI100's higher shading unit count and FP32 peak might offer some benefit, but the 49% benchmark deficit undermines that argument.

The production status of both cards is end-of-life, but the A100 was released on 2021-06-27, roughly seven months after the MI100's 2020-11-15 launch. The A100's predecessor is Tesla Turing, with Server Ada as its successor. The MI100's predecessor is Radeon Instinct, with no successor listed.

Specification Differences

The following specifications differ between the two accelerators:

| Specification | NVIDIA A100 PCIe 80 GB | AMD Instinct MI100 |

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

| Chip | GA100 | Arcturus |

| Architecture | Ampere | CDNA 1.0 |

| Generation | Server Ampere (Axx) | Instinct (MIx) |

| Transistors | 54,200 million | 25,600 million |

| Die Size | 826 mm² | 750 mm² |

| Transistor Density | 65.6M / mm² | 34.1M / mm² |

| Base Clock | 1065 MHz | 1000 MHz |

| Boost Clock | 1410 MHz | 1502 MHz |

| Memory Clock | 1512 MHz (3 Gbps effective) | 1200 MHz (2.4 Gbps effective) |

| Memory Size | 80 GB | 32 GB |

| Memory Type | HBM2e | HBM2 |

| Memory Bus Width | 5120 bit | 4096 bit |

| Memory Bandwidth | 1.94 TB/s | 1.23 TB/s |

| Shading Units | 6912 | 7680 |

| TMUs | 432 | 480 |

| ROPs | 160 | 64 |

| Tensor Cores | 432 | None |

| Pixel Rate | 225.6 GPixel/s | 96.13 GPixel/s |

| Texture Rate | 609.1 GTexel/s | 721.0 GTexel/s |

| FP32 | 19.49 TFLOPS | 23.07 TFLOPS |

| FP16 | 77.97 TFLOPS (4:1) | 46.14 TFLOPS (2:1) |

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

| Release Date | 2021-06-27 | 2020-11-15 |

| Predecessor | Tesla Turing | Radeon Instinct |

| Successor | Server Ada | None |

| OpenCL Score | 207,124 | 139,035 |

| Percentile | 99 | 96 |

Shared specifications include the 7 nm TSMC process, 300 W TDP, dual-slot form factor, 700 W suggested PSU, PCIe 4.0 x16 interface, no display outputs, and identical dimensions (267 mm length, 111 mm height).

FAQ

Q: Which GPU has a higher Geekbench OpenCL score?

A: The NVIDIA A100 PCIe 80 GB scores 207,124, which is 49% higher than the AMD Instinct MI100's 139,035.

Q: How does the A100 compare to its nearest rival, the NVIDIA RTX 6000D?

A: The A100's score of 207,124 is 5.7% higher than the RTX 6000D's average score of 195,964.

Q: What is the MI100's closest competitor in the benchmark data?

A: The NVIDIA Tesla V100 PCIe 16 GB, with an average score of 138,063, is only 0.7% behind the MI100's 139,035.

Q: Which GPU has more memory bandwidth?

A: The A100 provides 1.94 TB/s of bandwidth via HBM2e on a 5120-bit bus, while the MI100 provides 1.23 TB/s via HBM2 on a 4096-bit bus.

Q: Does the MI100 have tensor cores?

A: No, the AMD Instinct MI100 has no tensor cores, whereas the A100 integrates 432 tensor cores.

Q: Which card has higher FP32 throughput?

A: The MI100's FP32 peak is 23.07 TFLOPS, exceeding the A100's 19.49 TFLOPS, despite the A100's overall benchmark superiority.