AMD Radeon Pro 455 vs NVIDIA Tesla K20Xm Comparison

# The Verdict

The data presents a genuine split decision: the AMD Radeon Pro 455 dominates in Metal workloads, while the NVIDIA Tesla K20Xm crushes OpenCL compute. In the Geekbench Metal test, the Radeon Pro 455 scores 15,916 against the Tesla's 8,035—a 98.1% advantage. That is not a marginal gap; the AMD part delivers nearly double the Metal performance. Conversely, the Tesla K20Xm's OpenCL score of 17,215 versus 10,336 represents a 40% deficit for the Radeon Pro 455.

For users whose primary API is Metal—particularly those working within Apple's ecosystem, given the Radeon Pro 455's "Radeon Pro Mac (400 Series)" generation—the choice is obvious. The Radeon Pro 455 is a mobile-oriented MXM Module with a 35 W TDP, making it suitable for portable workstations. The Tesla K20Xm, by contrast, is a 235 W dual-slot accelerator with no display outputs, designed for compute servers. Its 6 GB memory and 384-bit bus offer 249.6 GB/s bandwidth, compared to the Radeon's 2 GB and 128-bit bus with 81.28 GB/s.

Both cards sit at the 52nd percentile among all GPUs, indicating they are middling performers overall. Their average benchmark scores are close: 12,831 for the Radeon Pro 455 and 12,625 for the Tesla K20Xm. The Radeon's nearest rival, the NVIDIA GeForce GTX 590, scores 12,830 (0% delta), while the Tesla's closest competitor, the AMD Radeon RX 7600M XT, scores 12,710 (-0.7%). Interestingly, the Radeon Pro 455 and Tesla K20Xm are rivals to each other, with the Tesla trailing by 1.6% in average score.

Choose the Radeon Pro 455 for Metal-centric workflows and low-power mobile deployment. Choose the Tesla K20Xm for OpenCL-heavy compute tasks where raw memory bandwidth and shading unit count matter more than API compatibility. The Tesla's 2,688 shading units dwarf the Radeon's 768, and its texture rate of 164.0 GTexel/s is four times the Radeon's 41.04 GTexel/s.

# Architecture Differences

The architectural chasm between these two GPUs is vast, reflecting their different design philosophies and release timelines. The AMD Radeon Pro 455 uses the "Baffin" chip built on GCN 4.0 architecture, fabricated on a 14 nm process at GlobalFoundries. It packs 3,000 million transistors into a 123 mm² die, yielding a transistor density of 24.4M per mm². The NVIDIA Tesla K20Xm, released nearly four years earlier, uses the "GK110" chip with Kepler architecture, built on TSMC's 28 nm process. It contains 7,080 million transistors across a massive 561 mm² die, with a density of just 12.6M per mm².

The Radeon Pro 455's newer process node gives it a density advantage: 24.4M transistors per square millimeter versus 12.6M for the Tesla. This is a direct consequence of the 14 nm versus 28 nm process gap. The AMD part also supports a newer API feature set: DirectX 12 (12_0) and Vulkan 1.3, while the Tesla only reaches DirectX 12 (11_0) and Vulkan 1.2.175. Both support OpenGL 4.6.

Memory configurations diverge sharply. The Radeon Pro 455 has 2 GB of GDDR5 on a 128-bit bus, delivering 81.28 GB/s bandwidth. The Tesla K20Xm offers 6 GB of GDDR5 on a 384-bit bus, achieving 249.6 GB/s—over three times the bandwidth. Their memory clocks are similar (1270 MHz versus 1300 MHz), but the Tesla's wider bus makes the difference. Effective memory speed is 5.1 Gbps for the Radeon and 5.2 Gbps for the Tesla.

Compute resources show an even starker contrast. The Tesla K20Xm has 2,688 shading units, 224 TMUs, and 48 ROPs. The Radeon Pro 455 has 768 shading units, 48 TMUs, and 16 ROPs. Pixel rate favors the Tesla at 40.99 GPixel/s versus 13.68 GPixel/s. Texture rate is 164.0 GTexel/s versus 41.04 GTexel/s. FP32 throughput is 3.935 TFLOPS for the Tesla versus 1,313.3 GFLOPS for the Radeon. Notably, the Radeon Pro 455 supports FP16 at 1,313.3 GFLOPS (1:1 ratio), while the Tesla lists no FP16 capability.

Physical and power characteristics differ fundamentally. The Radeon Pro 455 is an MXM Module with no power connectors and a 35 W TDP. The Tesla K20Xm is a dual-slot card measuring 267 mm (10.5 inches) in length, with a 235 W TDP and a suggested PSU of 550 W. The Radeon's bus interface is PCIe 3.0 x8; the Tesla uses PCIe 3.0 x16. Display outputs: the Radeon is "Portable Device Dependent," while the Tesla has no outputs at all—a pure compute accelerator.

# Where Each One Wins

The Radeon Pro 455's territory is Metal-based applications. Its Geekbench Metal score of 15,916 is nearly double the Tesla's 8,035, a 98.1% lead. This suggests the GCN 4.0 architecture with its newer API support is far better optimized for Apple's Metal framework. The Radeon also supports Vulkan 1.3 versus the Tesla's 1.2.175, giving it broader compatibility with modern cross-platform graphics APIs. Its 14 nm process and lower 35 W TDP make it suitable for portable devices, and its MXM Module form factor indicates it was designed for laptops or compact workstations.

The Tesla K20Xm wins decisively in raw OpenCL compute. Its score of 17,215 beats the Radeon's 10,336 by 40%. This aligns with its hardware: 2,688 shading units, 224 TMUs, and 249.6 GB/s memory bandwidth. For compute workloads that scale with shading unit count and memory bandwidth—such as scientific simulations, deep learning inference, or data processing—the Tesla is the stronger choice. Its 6 GB memory capacity also allows larger datasets to reside on-card versus the Radeon's 2 GB. The Tesla's predecessor is "Tesla Fermi" and its successor is "Tesla Maxwell," placing it in NVIDIA's dedicated compute accelerator line, whereas the Radeon Pro 455 belongs to AMD's professional Mac-oriented series.

The average benchmark scores tell a nuanced story. The Radeon Pro 455 averages 12,831, slightly ahead of the Tesla's 12,625. Both occupy the 52nd percentile among all GPUs. The Radeon's nearest rival, the GeForce GTX 590, scores 12,830 with a 0% delta, meaning the Radeon essentially ties that card. The Tesla's nearest rival, the Radeon RX 7600M XT, scores 12,710 with a -0.7% delta, meaning the Tesla trails it slightly. The GeForce GTX 670 appears in both lists, scoring 12,773 (0.5% ahead of the Radeon, 1.2% ahead of the Tesla).

# FAQ

Q: Which GPU has better Metal performance?

A: The AMD Radeon Pro 455 wins decisively in Geekbench Metal, scoring 15,916 versus the NVIDIA Tesla K20Xm's 8,035. This represents a 98.1% advantage for the Radeon.

Q: Which GPU is faster in OpenCL workloads?

A: The NVIDIA Tesla K20Xm leads in Geekbench OpenCL with a score of 17,215, compared to the AMD Radeon Pro 455's 10,336. The Tesla holds a 40% performance lead in this API.

Q: How do their memory configurations compare?

A: The Tesla K20Xm has 6 GB of GDDR5 memory on a 384-bit bus, providing 249.6 GB/s bandwidth. The Radeon Pro 455 has 2 GB of GDDR5 on a 128-bit bus, providing 81.28 GB/s.

Q: What are the power requirements for each card?

A: The Radeon Pro 455 has a 35 W TDP and uses an MXM Module form factor with no power connectors. The Tesla K20Xm has a 235 W TDP, a dual-slot design, and requires a 550 W suggested power supply.

Q: Which card has more shading units?

A: The Tesla K20Xm has 2,688 shading units, while the Radeon Pro 455 has 768. The Tesla also has 224 TMUs and 48 ROPs, versus the Radeon's 48 TMUs and 16 ROPs.

Q: Do both cards support the same graphics APIs?

A: No. The Radeon Pro 455 supports DirectX 12 (12_0), OpenGL 4.6, and Vulkan 1.3. The Tesla K20Xm supports DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175. The Radeon has a higher DirectX feature level and newer Vulkan version.

# Head-to-Head Benchmarks

The two available head-to-head benchmarks reveal a perfect split, with each card winning one test. The AMD Radeon Pro 455 takes the Geekbench Metal test with a score of 15,916 against the Tesla K20Xm's 8,035. The delta is 98.1%, meaning the Radeon nearly doubles the Tesla's Metal performance. This is the single largest performance gap in either direction. The Radeon's Metal advantage likely stems from its newer GCN 4.0 architecture and its design for the Mac ecosystem, as indicated by its "Radeon Pro Mac (400 Series)" generation label.

The NVIDIA Tesla K20Xm counters in Geekbench OpenCL, scoring 17,215 versus the Radeon's 10,336. The delta is -40%, indicating the Radeon trails by 40% in this test. The Tesla's OpenCL dominance aligns with its purpose-built compute design: 2,688 shading units provide massive parallel throughput, and the 384-bit memory bus delivers 249.6 GB/s bandwidth—more than triple the Radeon's 81.28 GB/s. The Tesla's FP32 throughput of 3.935 TFLOPS is also three times the Radeon's 1,313.3 GFLOPS.

Looking at the broader benchmark context, both cards average near 12,700-12,800 across all tests. The Radeon Pro 455's average is 12,831, while the Tesla K20Xm's is 12,625. This puts the Radeon 1.6% ahead of the Tesla in overall average score. Both GPUs sit at the 52nd percentile among all GPUs, meaning they outperform roughly half of all graphics cards ever benchmarked.

The Radeon Pro 455's nearest rivals include the GeForce GTX 590 (12,830, 0% delta), the AMD FirePro W5100 (12,847, -0.1%), and the AMD Radeon 740M (12,870, -0.3%). The Tesla K20Xm's nearest rivals include the Radeon RX 7600M XT (12,710, -0.7%), the GeForce GTX 670 (12,773, -1.2%), and the GeForce GTX 590 (12,830, -1.6%). Notably, the Radeon Pro 455 itself appears as a rival to the Tesla, with a -1.6% delta from the Tesla's perspective.

The texture rate gap is particularly telling: the Tesla's 164.0 GTexel/s versus the Radeon's 41.04 GTexel/s means the Tesla can fill textures four times faster. Pixel rates follow suit: 40.99 GPixel/s for the Tesla versus 13.68 GPixel/s for the Radeon. These raw throughput metrics explain the Tesla's OpenCL advantage, even though its older Kepler architecture and 28 nm process limit its API support. The Radeon's 14 nm process and GCN 4.0 architecture compensate with better driver optimization for modern APIs, particularly Metal.