AMD Radeon Pro 555X vs NVIDIA Tesla K20Xm Comparison

Head-to-Head Benchmarks

The benchmark data presents a sharply split picture between the AMD Radeon Pro 555X and the NVIDIA Tesla K20Xm. Across the two shared tests, each card claims a decisive victory, with no close contests in either direction.

In the Geekbench Metal test, the AMD Radeon Pro 555X posts a score of 14,479 against the Tesla K20Xm’s 8,035. That is an 80.2% advantage for AMD, a massive margin that underscores the Tesla’s fundamental unsuitability for Apple’s Metal API. The Tesla K20Xm’s Metal score is not merely lower; it is categorically in a different performance tier, placing it in the company of much older or lower-end parts.

The Geekbench OpenCL test flips the script entirely. Here, the NVIDIA Tesla K20Xm scores 17,215, while the AMD Radeon Pro 555X manages 12,628. The delta is 26.6% in NVIDIA’s favor. This is a substantial lead, reflecting the Tesla’s raw compute throughput and its design intent as a high-performance accelerator for OpenCL workloads, which were common in scientific and professional computing during its era.

The overall average benchmark scores tell a story of near-parity despite these divergent wins. The AMD card’s average across its three tested APIs (Metal, OpenCL, Vulkan) is 13,321. The NVIDIA card’s average across its two tested APIs (Metal, OpenCL) is 12,625. This puts the AMD part roughly 5.5% ahead in aggregate, but that figure masks the significant per-API swings. The AMD Radeon Pro 555X also holds a slight edge in overall percentile ranking, sitting at the 54th percentile among all GPUs tested, versus the Tesla K20Xm’s 52nd percentile.

Looking at nearest rivals provides additional context. The AMD Radeon Pro 555X (average 13,321) is essentially tied with the NVIDIA GeForce GTX 480, which averages 13,300, a delta of just 0.2%. It is also virtually indistinguishable from the AMD FirePro M6100 (13,354, delta -0.2%) and the AMD Radeon RX 5500M (13,356, delta -0.3%). The Tesla K20Xm (average 12,625) sits close to the AMD Radeon RX 7600M XT (12,710, delta -0.7%) and the NVIDIA GeForce GTX 670 (12,773, delta -1.2%). These rival comparisons indicate that neither card is an outlier in its performance class; both land squarely in a mid-range bracket defined by aggregate compute scores.

The Verdict

The data supports a clear, workload-driven verdict. For any task leveraging Apple’s Metal API, the AMD Radeon Pro 555X is the only rational choice. Its 80.2% lead in the Metal benchmark is not a marginal improvement; it is a disqualifying gap for the Tesla K20Xm. The AMD part’s Metal score of 14,479 is its strongest result, suggesting that its GCN 4.0 architecture is well-optimized for this modern API. In contrast, the Tesla’s Metal score of 8,035 is its weakest, indicating a fundamental lack of support or optimization.

Conversely, for pure OpenCL compute throughput, the NVIDIA Tesla K20Xm is the superior performer. Its 26.6% advantage over the AMD card in OpenCL demonstrates its strength as a compute-oriented accelerator. With 2,688 shading units and a 384-bit memory bus delivering 249.6 GB/s of bandwidth, the Tesla was engineered for high-throughput parallel computation, and the OpenCL benchmark reflects that design philosophy.

The choice, therefore, is not about which GPU is “better” in a vacuum. It is about the target software environment. A user or system integrating with macOS and Metal-centric applications should select the AMD Radeon Pro 555X without hesitation. A professional running Linux or Windows with OpenCL-based scientific or engineering workloads would find the Tesla K20Xm’s higher raw compute score more compelling. The Tesla’s 6 GB of memory, 50% more than the AMD’s 4 GB, also provides a capacity advantage for large datasets, although the AMD’s newer 14 nm process and higher transistor density (24.4M per mm² versus the Tesla’s 12.6M per mm²) indicate a more modern, efficient design.

Architecture Differences

The two GPUs represent fundamentally different architectural eras and design goals. The AMD Radeon Pro 555X is built on the Polaris 21 chip using the GCN 4.0 architecture, fabricated on a 14 nm process at GlobalFoundries. It packs 3,000 million transistors into a die size of 123 mm², yielding a transistor density of 24.4 million per square millimeter. This is a mobile-oriented, power-efficient design with a TDP of 75 W and an integrated form factor (IGP slot width), requiring no power connectors.

The NVIDIA Tesla K20Xm, by contrast, is a high-performance compute card built on the GK110 chip using the Kepler architecture, fabricated on a 28 nm process at TSMC. It contains 7,080 million transistors across a massive 561 mm² die, but its transistor density is much lower at 12.6 million per square millimeter. This part has a TDP of 235 W, requires a 550 W suggested PSU, and occupies a dual-slot form factor with a length of 267 mm (10.5 inches). It has no display outputs, confirming its role as a dedicated compute accelerator.

The compute resources differ dramatically. The Tesla K20Xm has 2,688 shading units, 224 texture mapping units, and 48 render output units. The AMD Radeon Pro 555X has 768 shading units, 48 TMUs, and 16 ROPs. The Tesla’s raw execution width is far larger, which explains its OpenCL advantage. However, the AMD part achieves higher pixel and texture rates per unit of silicon, with a pixel rate of 14.51 GPixel/s and texture rate of 43.54 GTexel/s, versus the Tesla’s 40.99 GPixel/s and 164.0 GTexel/s, respectively. The Tesla’s FP32 throughput is listed at 3.935 TFLOPS, more than double the AMD’s 1,393.2 GFLOPS.

Memory configurations also diverge. The AMD card uses 4 GB of GDDR5 on a 128-bit bus, delivering 94.08 GB/s of bandwidth. The Tesla provides 6 GB of GDDR5 on a 384-bit bus, achieving 249.6 GB/s. The Tesla’s memory clock is 1300 MHz (5.2 Gbps effective), while the AMD runs at 1470 MHz (5.9 Gbps effective), indicating the AMD’s memory is faster per pin but narrower overall. The bus interface also differs: the AMD uses PCIe 3.0 x8, while the Tesla uses PCIe 3.0 x16, providing the Tesla with double the host link bandwidth.

API support shows the AMD part’s modern pedigree. It supports DirectX 12 (12_0), OpenGL 4.6, and Vulkan 1.3. The Tesla supports DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175 — a slightly older Vulkan revision. The AMD card also has a native 1:1 FP16 to FP32 ratio, while the Tesla has no listed FP16 capability, which is significant for workloads using half-precision arithmetic.

FAQ

Q: Which GPU has the higher average benchmark score across all tested APIs?

A: The AMD Radeon Pro 555X has an average benchmark score of 13,321, compared to the NVIDIA Tesla K20Xm’s 12,625, giving the AMD part a lead of approximately 5.5%.

Q: How large is the performance gap in the Geekbench Metal test?

A: The AMD Radeon Pro 555X scores 14,479 in Metal, while the NVIDIA Tesla K20Xm scores 8,035. This represents an 80.2% advantage for the AMD card.

Q: What is the memory capacity difference between the two cards?

A: The NVIDIA Tesla K20Xm has 6 GB of GDDR5 memory, while the AMD Radeon Pro 555X has 4 GB of GDDR5. The Tesla’s memory bus is 384-bit versus the AMD’s 128-bit, resulting in 249.6 GB/s bandwidth for the Tesla and 94.08 GB/s for the AMD.

Q: Which card has a higher transistor count and die size?

A: The NVIDIA Tesla K20Xm has 7,080 million transistors on a 561 mm² die, while the AMD Radeon Pro 555X has 3,000 million transistors on a 123 mm² die. The AMD part has a much higher transistor density at 24.4M per mm² versus the Tesla’s 12.6M per mm².

Q: What are the TDP requirements for each card?

A: The AMD Radeon Pro 555X has a TDP of 75 W and requires no power connectors, fitting an IGP slot width. The NVIDIA Tesla K20Xm has a TDP of 235 W, requires a 550 W suggested PSU, and occupies a dual-slot form factor.

Q: When was each GPU released?

A: The AMD Radeon Pro 555X was released on July 15, 2018. The NVIDIA Tesla K20Xm was released earlier, on November 11, 2012. Both are end-of-life products.

Where Each One Wins

The AMD Radeon Pro 555X wins decisively in the Geekbench Metal benchmark, with a score of 14,479 that is 80.2% higher than the Tesla’s 8,035. This makes it the clear choice for any application built on Apple’s Metal graphics API, including macOS-native creative software, game engines, and GPU-accelerated rendering tools that leverage Metal. The AMD card also wins in overall average benchmark score (13,321 versus 12,625) and holds a higher percentile ranking (54th versus 52nd). Its support for Vulkan 1.3 and DirectX 12 (12_0) gives it broader modern API compatibility, and its 14 nm process and 75 W TDP make it far more power-efficient and suitable for portable or integrated systems.

The NVIDIA Tesla K20Xm wins the Geekbench OpenCL test by a substantial margin, scoring 17,215 against the AMD’s 12,628, a 26.6% advantage. This makes it the superior choice for OpenCL-based compute workloads, such as scientific simulation, data analysis, and general-purpose GPU computing on platforms that rely on OpenCL for acceleration. The Tesla also offers more memory (6 GB versus 4 GB) and significantly higher memory bandwidth (249.6 GB/s versus 94.08 GB/s), which benefits large datasets and memory-bound kernels. Its 2,688 shading units and 3.935 TFLOPS FP32 throughput provide raw compute power that the AMD part cannot match, making it the preferred option for headless compute nodes or servers where display output is unnecessary.

In summary, the AMD Radeon Pro 555X is the winner for modern, API-diverse, power-constrained environments, particularly those within Apple’s ecosystem. The NVIDIA Tesla K20Xm is the winner for legacy OpenCL compute tasks that demand maximum throughput and memory capacity, accepting its higher power draw and lack of display outputs. The two cards are not direct substitutes; they serve different purposes and excel in different domains, as the benchmark data clearly demonstrates.