AMD Radeon Pro 555X vs NVIDIA Tesla K20c Comparison

The Verdict

The recorded data points to a clear but narrow winner: the AMD Radeon Pro 555X. In the only shared benchmark, Geekbench OpenCL, the AMD part scores 12,628 against the NVIDIA Tesla K20c’s 11,479, a 10% advantage. The AMD card also holds a higher overall percentile ranking, sitting at the 54th percentile of all GPUs while the Tesla rests at the 51st. For any workload that relies on OpenCL compute, the Radeon Pro 555X is the safer pick based on measured performance alone.

However, the Tesla K20c is not without reason for consideration. It offers substantially more memory (5 GB versus 4 GB), a wider memory bus (320 bit versus 128 bit), and more than double the bandwidth (208.0 GB/s versus 94.08 GB/s). If the task is memory-bound rather than compute-bound, the Tesla’s larger frame buffer and faster memory subsystem could matter more than the raw OpenCL score. The AMD part wins on compute efficiency and newer architecture, while the Tesla wins on memory capacity and throughput.

For a user prioritizing OpenCL compute speed and architectural modernity, the Radeon Pro 555X is the choice. For a user needing maximum memory capacity and bandwidth in a dual-slot card with no display outputs, the Tesla K20c fits that niche. The data does not support a universal winner; it supports a split decision based on workload type.

Architecture Differences

The two GPUs come from different manufacturing generations and design philosophies. The AMD Radeon Pro 555X uses the Polaris 21 chip built on GCN 4.0 architecture, fabricated on a 14 nm process at GlobalFoundries. The NVIDIA Tesla K20c uses the GK110 chip on Kepler architecture, fabricated on a 28 nm process at TSMC. The process node difference is stark: 14 nm versus 28 nm, which explains the AMD chip’s far higher transistor density of 24.4 million transistors per square millimeter versus 12.6 million for the NVIDIA chip.

Transistor counts tell a complementary story. The Tesla K20c packs 7,080 million transistors on a 561 mm² die, while the Radeon Pro 555X has just 3,000 million on a 123 mm² die. The Tesla is a much larger, more complex chip, but the AMD part achieves better OpenCL performance per transistor. The AMD chip’s die is roughly one-fifth the area of the Tesla’s, yet it delivers a 10% higher OpenCL score.

Shading resources differ dramatically. The Tesla K20c has 2,496 shading units, 208 texture mapping units, and 40 render output units. The Radeon Pro 555X has 768 shading units, 48 TMUs, and 16 ROPs. Despite having roughly one-third the shading units, the AMD card wins the OpenCL benchmark. This indicates that GCN 4.0’s instruction efficiency and the 14 nm process’s higher clocks (memory clock of 1470 MHz versus 1300 MHz) offset the raw unit count deficit.

API support also diverges. The AMD card lists DirectX 12 (12_0), OpenGL 4.6, and Vulkan 1.3. The Tesla lists DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175. The AMD part has a newer Vulkan version and a higher DirectX feature level, which may affect compatibility with modern titles and compute frameworks. The Tesla has no display outputs, making it a pure compute accelerator, while the AMD part’s outputs are portable device dependent, meaning it was designed for integrated use in a laptop chassis.

Head-to-Head Benchmarks

The only direct comparison available in the database is the Geekbench OpenCL test. The AMD Radeon Pro 555X scores 12,628, and the NVIDIA Tesla K20c scores 11,479. The delta is 10% in favor of AMD. This is a meaningful gap in a compute benchmark that exercises floating-point throughput and memory access patterns. The AMD card’s FP32 performance is listed at 1,393.2 GFLOPS, while the Tesla’s is 3.524 TFLOPS (which is 3,524 GFLOPS). The Tesla has more than double the theoretical FP32 throughput, yet it loses the OpenCL test. This suggests the Geekbench OpenCL workload is not purely arithmetic; it likely rewards memory latency, driver efficiency, or architectural features like GCN’s compute-focused design.

The AMD card also has a 1:1 FP16 to FP32 ratio, meaning it can process half-precision at the same rate as single-precision. The Tesla lists no FP16 support in the database. For workloads that use FP16, the AMD card has a clear advantage, though the OpenCL benchmark may not specifically test this.

Pixel and texture rates favor the Tesla. The Tesla achieves 36.71 GPixel/s and 146.8 GTexel/s, versus the AMD card’s 14.51 GPixel/s and 43.54 GTexel/s. These are large margins, but neither GPU is marketed for rasterization in this context: the Tesla has no display outputs, and the AMD part is an integrated laptop GPU. The OpenCL score remains the primary measured differentiator.

FAQ

Q: Which GPU has the higher average benchmark score?

A: The AMD Radeon Pro 555X has an average benchmark score of 13,321, while the NVIDIA Tesla K20c has 11,479. The AMD card is ahead by roughly 16%.

Q: Does the Tesla K20c have more memory than the Radeon Pro 555X?

A: Yes. The Tesla K20c has 5 GB of GDDR5 on a 320 bit bus with 208.0 GB/s bandwidth. The Radeon Pro 555X has 4 GB of GDDR5 on a 128 bit bus with 94.08 GB/s bandwidth.

Q: Which card is more power-efficient based on the data?

A: The Radeon Pro 555X has a TDP of 75 W, while the Tesla K20c is rated at 225 W. The AMD card delivers a higher OpenCL score at one-third the power draw.

Q: What is the launch MSRP of the Tesla K20c?

A: The Tesla K20c had a launch MSRP of 3,199 USD. No launch MSRP is listed for the Radeon Pro 555X.

Q: Can the Tesla K20c output video?

A: No. The database lists its display outputs as "No outputs," making it a compute-only accelerator. The Radeon Pro 555X’s outputs are portable device dependent.

Q: Which GPU has a higher percentile ranking?

A: The Radeon Pro 555X ranks at the 54th percentile of all GPUs, while the Tesla K20c ranks at the 51st percentile.

Where Each One Wins

The AMD Radeon Pro 555X wins in OpenCL compute performance, posting a 10% higher score than the Tesla K20c. It also wins on architectural efficiency: a smaller die (123 mm² versus 561 mm²), a newer process node (14 nm versus 28 nm), higher transistor density (24.4M/mm² versus 12.6M/mm²), and a much lower TDP (75 W versus 225 W). For any scenario where power draw is a constraint, such as a laptop chassis, the AMD card is clearly superior. Its API support is also newer, with Vulkan 1.3 and DirectX 12 (12_0), which may grant better compatibility with current software stacks.

The NVIDIA Tesla K20c wins on memory capacity and bandwidth. With 5 GB versus 4 GB, a 320 bit bus versus 128 bit, and 208.0 GB/s versus 94.08 GB/s, it is the better choice for datasets that exceed 4 GB or for workloads that stream large amounts of data. It also has higher pixel and texture rates, though these are less relevant for a compute-only card. The Tesla’s dual-slot form factor and 1x 6-pin plus 1x 8-pin power connectors indicate a desktop workstation design, whereas the AMD card is an integrated part with no power connectors. For a server or workstation with a 550 W suggested PSU, the Tesla fits a traditional add-in card slot.

The use-case split is clean: choose the Radeon Pro 555X for efficient, modern compute in a power-limited environment; choose the Tesla K20c for memory-heavy compute in a desktop or server where power and space are not constraints.

Specification Differences

The two GPUs differ across nearly every category in the database. The process node is 14 nm for AMD versus 28 nm for NVIDIA. The foundry is GlobalFoundries for AMD, TSMC for NVIDIA. Transistor count is 3,000 million versus 7,080 million, and die size is 123 mm² versus 561 mm². Transistor density is 24.4M/mm² versus 12.6M/mm².

Memory configurations diverge: 4 GB versus 5 GB, both GDDR5, but with bus widths of 128 bit versus 320 bit. Memory bandwidth is 94.08 GB/s versus 208.0 GB/s. Memory clock is 1470 MHz (5.9 Gbps effective) for AMD, and 1300 MHz (5.2 Gbps effective) for NVIDIA.

Compute resources differ: 768 shading units versus 2,496, 48 TMUs versus 208, and 16 ROPs versus 40. Pixel rate is 14.51 GPixel/s versus 36.71 GPixel/s, and texture rate is 43.54 GTexel/s versus 146.8 GTexel/s. FP32 throughput is 1,393.2 GFLOPS versus 3.524 TFLOPS. The AMD card lists FP16 at 1,393.2 GFLOPS (1:1), while the Tesla lists no FP16.

Power and physical specs: TDP is 75 W versus 225 W. The AMD card is integrated (IGP slot width) with no power connectors; the Tesla is dual-slot with 1x 6-pin plus 1x 8-pin and a suggested PSU of 550 W. Bus interface is PCIe 3. The AMD card uses PCIe 3.0 x8, while the Tesla uses PCIe 2.0 x16. Display outputs are portable device dependent for AMD and none for NVIDIA. The Tesla has a length of 267 mm (10.5 inches), while the AMD card lists no dimensions. API support: AMD lists DirectX 12 (12_0), OpenGL 4.6, Vulkan 1.3; NVIDIA lists DirectX 12 (11_0), OpenGL 4.6, Vulkan 1.2. Release dates are 2018-07-15 for AMD and 2012-11-11 for NVIDIA. The Tesla’s predecessor is Tesla Fermi and successor is Tesla Maxwell; the AMD card lists no predecessor or successor. The Tesla had a launch MSRP of 3,199 USD, and both are end-of-life.