AMD Radeon Pro 455 vs NVIDIA Tesla K20c Comparison

The NVIDIA Tesla K20c and AMD Radeon Pro 455 occupy different ends of the GPU spectrum, with the data showing a clear but narrow victory for the older Tesla part in the only directly comparable benchmark. In the Geekbench OpenCL test, the Tesla K20c scores 11,479 against the Radeon Pro 455’s 10,336, a decisive 11.1% advantage. This head-to-head result, however, does not tell the full story, as the Radeon Pro 455’s average benchmark score of 12,831 across multiple APIs surpasses the Tesla’s 11,479 average, driven by its superior performance in Metal and Vulkan workloads. The benchmark results indicate that while the Tesla K20c wins the OpenCL comparison, the Radeon Pro 455 is the more versatile performer in modern compute environments.

Head-to-Head Benchmarks

The sole direct comparison available is the Geekbench OpenCL test, where the NVIDIA Tesla K20c emerges victorious with a score of 11,479 against the AMD Radeon Pro 455’s 10,336. This 11.1% delta represents a meaningful performance gap, one that aligns with the Tesla’s substantially larger silicon and compute resources. The Tesla K20c’s nearest rivals in the overall database include the NVIDIA GeForce GTX 1660 (scoring 11,680, a 1.7% advantage over the Tesla) and the AMD Radeon RX 7800 XT (scoring 11,627, 1.3% ahead), placing the Tesla in a competitive mid-range position despite its age. Conversely, the Radeon Pro 455’s OpenCL score is 4.8% behind its average across all benchmarks, indicating that OpenCL is not its strongest API.

Expanding the view to all benchmark results, the Radeon Pro 455 shows a different profile. Its Geekbench Metal score of 15,916 is its highest, while its Vulkan score of 12,240 also exceeds the Tesla’s OpenCL number. The Radeon Pro 455’s average benchmark score of 12,831 places it in the 52nd percentile of all GPUs, slightly ahead of the Tesla K20c’s 51st percentile. The Radeon Pro 455’s nearest rivals include the NVIDIA GeForce GTX 590 (scoring 12,830, a 0% delta) and the AMD FirePro W5100 (scoring 12,847, 0.1% behind), showing that it sits in a tightly contested performance bracket. In contrast, the Tesla K20c’s nearest rival, the AMD Radeon Pro 5500M, scores 11,528, a 0.4% edge over the Tesla. The data shows that the Tesla K20c’s win in OpenCL is narrow in the context of its peer group, while the Radeon Pro 455’s multi-API strength gives it a higher overall standing.

Architecture Differences

The architectural divide between these two GPUs is stark, reflecting their different design eras and purposes. The NVIDIA Tesla K20c is built on the Kepler architecture using the GK110 chip, fabricated on a 28 nm process at TSMC. This chip contains 7,080 million transistors on a 561 mm² die, yielding a transistor density of 12.6 million per square millimeter. The AMD Radeon Pro 455, by contrast, uses the Baffin chip with GCN 4.0 architecture, manufactured on a 14 nm process at GlobalFoundries. It packs 3,000 million transistors into a 123 mm² die, achieving a transistor density of 24.4 million per square millimeter — nearly double that of the Tesla, showcasing the efficiency gains of the newer process node.

Compute resources differ dramatically. The Tesla K20c fields 2,496 shading units, 208 texture mapping units, and 40 raster output pipelines. The Radeon Pro 455 is far leaner, with 768 shading units, 48 TMUs, and 16 ROPs. These numbers explain the Tesla’s raw throughput advantages: it delivers 3.524 TFLOPS of FP32 performance, 146.8 GTexel/s of texture fill rate, and 36.71 GPixel/s of pixel rate. The Radeon Pro 455 counters with 1,313.3 GFLOPS of FP32 (and FP16 at a 1:1 ratio), 41.04 GTexel/s, and 13.68 GPixel/s. In every throughput metric, the Tesla holds a commanding lead, though the Radeon’s FP16 capability — matching its FP32 rate — is a feature the Tesla lacks entirely, as it has no listed FP16 support.

Memory subsystems also diverge. The Tesla K20c has 5 GB of GDDR5 on a 320-bit bus, delivering 208.0 GB/s of bandwidth with memory clocked at 1300 MHz (5.2 Gbps effective). The Radeon Pro 455 has 2 GB of GDDR5 on a 128-bit bus, yielding 81.28 GB/s of bandwidth at 1270 MHz (5.1 Gbps effective). The Tesla’s memory bandwidth is 2.56 times higher, a critical factor for data-intensive workloads. The bus interfaces differ as well: the Tesla uses PCIe 2.0 x16, while the Radeon Pro 455 uses PCIe 3.0 x8, which offers similar theoretical bandwidth but reflects the AMD part’s newer platform compatibility. Power consumption is another major divider, with the Tesla rated at 225 W TDP requiring both a 6-pin and 8-pin power connector, while the Radeon Pro 455 sips just 35 W TDP and requires no external power connectors.

Where Each One Wins

The Tesla K20c wins in scenarios that demand raw compute throughput and memory bandwidth. Its 3.524 TFLOPS of FP32 performance is 2.68 times higher than the Radeon Pro 455’s 1,313.3 GFLOPS, making it the clear choice for compute-heavy OpenCL workloads, as evidenced by its 11.1% head-to-head win. The 208.0 GB/s memory bandwidth versus 81.28 GB/s gives the Tesla a substantial advantage in tasks that stream large datasets, such as scientific simulations or large matrix operations. The Tesla’s 5 GB memory capacity, more than double the Radeon’s 2 GB, allows it to hold larger working sets without spilling to system memory. Its dual-slot form factor and 225 W power envelope, while demanding, signal a card designed for sustained professional compute, not efficiency-constrained environments.

The Radeon Pro 455 wins in versatility and modern API support. Its Geekbench Metal score of 15,916 and Vulkan score of 12,240 demonstrate strong performance in APIs that the Tesla cannot even run, as the Tesla’s API list includes DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175, while the Radeon Pro 455 supports DirectX 12 (12_0), OpenGL 4.6, and Vulkan 1.3. The Radeon’s higher Vulkan version and full DirectX 12_0 support make it more compatible with contemporary software. The Radeon Pro 455’s 35 W TDP and MXM module form factor make it suitable for portable devices, with display outputs described as "Portable Device Dependent," whereas the Tesla K20c has no display outputs at all, making it exclusively a compute accelerator. The Radeon’s FP16 capability, matching its FP32 throughput, is another modern feature absent from the Tesla, beneficial for AI inference and graphics workloads that leverage half-precision arithmetic.

FAQ

Q: Which GPU has the higher average benchmark score?

A: The AMD Radeon Pro 455 has an average benchmark score of 12,831, compared to the NVIDIA Tesla K20c’s 11,479, placing the Radeon in the 52nd percentile versus the Tesla’s 51st.

Q: What is the performance difference in the OpenCL benchmark?

A: In the Geekbench OpenCL test, the NVIDIA Tesla K20c scores 11,479 against the AMD Radeon Pro 455’s 10,336, giving the Tesla an 11.1% advantage.

Q: How do their transistor counts and die sizes compare?

A: The Tesla K20c contains 7,080 million transistors on a 561 mm² die, while the Radeon Pro 455 has 3,000 million transistors on a 123 mm² die, with the Radeon having nearly double the transistor density at 24.4M per mm² versus 12.6M per mm².

Q: Which GPU supports more modern APIs?

A: The Radeon Pro 455 supports DirectX 12 (12_0) and Vulkan 1.3, while the Tesla K20c supports DirectX 12 (11_0) and Vulkan 1.2.175, giving the Radeon the edge in API versioning.

Q: What are the memory specifications of each GPU?

A: The Tesla K20c has 5 GB of GDDR5 on a 320-bit bus with 208.0 GB/s bandwidth, while the Radeon Pro 455 has 2 GB of GDDR5 on a 128-bit bus with 81.28 GB/s bandwidth.

Q: How do their power requirements differ?

A: The Tesla K20c has a 225 W TDP and requires both a 6-pin and 8-pin power connector, while the Radeon Pro 455 has a 35 W TDP and requires no external power connectors.

Specification Differences

| Specification | NVIDIA Tesla K20c | AMD Radeon Pro 455 |

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

| Architecture | Kepler | GCN 4.0 |

| Process Node | 28 nm | 14 nm |

| Foundry | TSMC | GlobalFoundries |

| Transistors | 7,080 million | 3,000 million |

| Die Size | 561 mm² | 123 mm² |

| Transistor Density | 12.6M / mm² | 24.4M / mm² |

| Memory Size | 5 GB | 2 GB |

| Memory Bus Width | 320 bit | 128 bit |

| Memory Bandwidth | 208.0 GB/s | 81.28 GB/s |

| Memory Clock | 1300 MHz (5.2 Gbps effective) | 1270 MHz (5.1 Gbps effective) |

| Shading Units | 2,496 | 768 |

| TMUs | 208 | 48 |

| ROPs | 40 | 16 |

| Pixel Rate | 36.71 GPixel/s | 13.68 GPixel/s |

| Texture Rate | 146.8 GTexel/s | 41.04 GTexel/s |

| FP32 Performance | 3.524 TFLOPS | 1,313.3 GFLOPS |

| FP16 Performance | N/A | 1,313.3 GFLOPS (1:1) |

| TDP | 225 W | 35 W |

| Slot Width | Dual-slot | MXM Module |

| Power Connectors | 1x 6-pin + 1x 8-pin | None |

| Bus Interface | PCIe 2.0 x16 | PCIe 3.0 x8 |

| Display Outputs | No outputs | Portable Device Dependent |

| DirectX Version | 12 (11_0) | 12 (12_0) |

| Vulkan Version | 1.2.175 | 1.3 |

| Release Date | 2012-11-11 | 2016-10-29 |

| Launch MSRP | 3,199 USD | N/A |

The Verdict

The data points to a clear split: choose the NVIDIA Tesla K20c for raw compute throughput in OpenCL-centric workflows, and choose the AMD Radeon Pro 455 for modern API support and efficiency. The Tesla K20c’s 11.1% OpenCL win, combined with its 3.524 TFLOPS FP32 performance and 208.0 GB/s memory bandwidth, makes it the superior choice for number-crunching tasks that rely on the OpenCL ecosystem. Its 5 GB memory capacity is also a practical advantage for large datasets. However, this comes at the cost of a 225 W TDP, requiring a 550 W suggested PSU and dual-slot chassis space, with no display outputs.

The AMD Radeon Pro 455, despite losing the OpenCL head-to-head, presents a more balanced profile. Its average benchmark score of 12,831 exceeds the Tesla’s 11,479, driven by strong Metal (15,916) and Vulkan (12,240) results. The Radeon’s support for DirectX 12 (12_0) and Vulkan 1.3, alongside FP16 compute at 1:1 ratio, positions it better for contemporary software stacks. Its 35 W TDP and MXM form factor make it the only viable option for portable or power-constrained systems. For users prioritizing efficiency, modern API compatibility, and a higher overall benchmark average, the Radeon Pro 455 is the data-supported pick; for those needing maximum FP32 throughput and memory bandwidth in a workstation, the Tesla K20c wins on the merits of its compute specifications.