AMD Radeon HD 8950M vs NVIDIA Tesla K20Xm Comparison

FAQ

Q: Which GPU wins in the Geekbench OpenCL benchmark?

A: The NVIDIA Tesla K20Xm wins, scoring 17,215 versus the AMD Radeon HD 8950M’s 13,772. That is a 20% advantage for the Tesla K20Xm in this specific test.

Q: Are there any benchmark tests where the AMD Radeon HD 8950M comes out ahead?

A: No. In the only head-to-head benchmark recorded, the NVIDIA Tesla K20Xm wins. The AMD card has no benchmark wins in the data, while the Tesla has one.

Q: How do these two cards compare to their closest rivals in average benchmark score?

A: The AMD Radeon HD 8950M has an average benchmark score of 13,376, placing it 0.2% ahead of the AMD Radeon RX 5500M and the AMD FirePro M6100, and 0.4% ahead of the AMD Radeon Pro 555X. The NVIDIA Tesla K20Xm averages 12,625, sitting 0.7% behind the AMD Radeon RX 7600M XT and 1.6% behind both the NVIDIA GeForce GTX 590 and AMD Radeon Pro 455.

Q: What is the difference in memory capacity and bandwidth between the two?

A: The AMD Radeon HD 8950M has 2 GB of GDDR5 on a 128-bit bus, yielding 88.00 GB/s of bandwidth. The NVIDIA Tesla K20Xm has 6 GB of GDDR5 on a 384-bit bus, delivering 249.6 GB/s. The Tesla has three times the capacity and nearly three times the bandwidth.

Q: Do both cards support the same DirectX version?

A: No. The AMD Radeon HD 8950M supports DirectX 12 (12_0), while the NVIDIA Tesla K20Xm supports DirectX 12 (11_0). Both support OpenGL 4.6, but the NVIDIA card has a slightly newer Vulkan version at 1.2.175 compared to AMD’s 1.2.170.

Q: What are the physical and power differences between them?

A: The AMD Radeon HD 8950M is an MXM Module with a 100 W TDP; the NVIDIA Tesla K20Xm is a Dual-slot card with a 235 W TDP and a suggested PSU of 550 W. The Tesla is also a long card at 267 mm (10.5 inches) and has no display outputs, unlike the AMD which is "Portable Device Dependent" for outputs.

The Verdict

The data points to a clear split: the NVIDIA Tesla K20Xm is the raw compute beast, while the AMD Radeon HD 8950M is the more balanced mobile part. In Geekbench OpenCL, the Tesla leads by 20% — a decisive margin that reflects its far larger silicon and memory subsystem. However, the AMD card holds a higher average benchmark score overall (13,376 vs 12,625) and a better percentile ranking (54th vs 52nd percentile of all GPUs). The AMD part also edges out its nearest rivals, while the Tesla sits slightly below its closest competitors.

For a pure compute workload where OpenCL performance is king, the Tesla K20Xm is the obvious pick. It has 6 GB of VRAM, 249.6 GB/s of bandwidth, and a 3.935 TFLOPS FP32 rate — all far beyond the AMD card. But it’s a dual-slot, 235 W behemoth with no display outputs, requiring a 550 W PSU. The AMD Radeon HD 8950M, by contrast, fits in a portable device at 100 W and offers a more modern DirectX 12 (12_0) feature set. If you need a card for a laptop or a compact MXM system with modest power, the AMD is the sensible choice. If you need maximum compute throughput in a stationary workstation, the Tesla wins outright.

Head-to-Head Benchmarks

The only direct benchmark comparison is Geekbench OpenCL, and it is a landslide for NVIDIA. The Tesla K20Xm scores 17,215, versus the AMD Radeon HD 8950M’s 13,772. The delta is 20% in NVIDIA’s favor. That’s not a small gap; it’s the kind of difference that matters in render farms or compute clusters where every bit of throughput counts.

The AMD card’s 13,772 OpenCL score is respectable, but it lands 3,443 points behind the Tesla. In percentage terms, the AMD card would need roughly a 25% improvement to tie the Tesla. The Tesla’s 3.935 TFLOPS FP32 rate is more than double the AMD’s 1.651 TFLOPS, which explains the OpenCL result. The texture and pixel rates tell the same story: the Tesla pushes 164.0 GTexel/s and 40.99 GPixel/s, while the AMD manages 51.60 GTexel/s and 17.20 GPixel/s.

Interestingly, the AMD card has a higher average benchmark score across all tests (13,376 vs 12,625), despite losing the one head-to-head test. This suggests the AMD card’s other benchmark results (Geekbench Vulkan at 12,979) help its overall standing, while the Tesla’s Geekbench Metal score of 8,035 drags its average down. The wins tally is 1-0 in favor of the Tesla, but the average score narrative favors AMD.

Specification Differences

The two cards diverge sharply on nearly every hardware specification. The memory subsystem is the most obvious differentiator: AMD has 2 GB GDDR5 on a 128-bit bus (88.00 GB/s), while NVIDIA has 6 GB GDDR5 on a 384-bit bus (249.6 GB/s). The Tesla has triple the capacity and 2.8 times the bandwidth.

Compute resources are equally lopsided. The AMD Radeon HD 8950M has 768 shading units, 48 TMUs, and 16 ROPs. The NVIDIA Tesla K20Xm has 2,688 shading units, 224 TMUs, and 48 ROPs. That’s 3.5 times the shading units, 4.7 times the TMUs, and 3 times the ROPs. The FP32 throughput follows: 1.651 TFLOPS for AMD versus 3.935 TFLOPS for NVIDIA.

Memory clocks are similar (1375 MHz for AMD, 1300 MHz for NVIDIA), but the bus width difference dominates. The TDP gap is substantial: 100 W for the AMD MXM module versus 235 W for the NVIDIA dual-slot card. The Tesla also requires a 550 W suggested PSU, while the AMD has no such requirement listed. The Tesla is 267 mm long and has no display outputs; the AMD is portable-device dependent for outputs. The AMD supports DirectX 12 (12_0), while the Tesla only reaches DirectX 12 (11_0). Vulkan support is slightly newer on the Tesla (1.2.175 vs 1.2.170).

Architecture Differences

The AMD Radeon HD 8950M is built on GCN 2.0 architecture using the Saturn chip, part of the Solar System (HD 8900M) generation. The NVIDIA Tesla K20Xm uses the Kepler architecture with the GK110 chip, from the Tesla Kepler (Kxx) generation. Both are fabricated on TSMC’s 28 nm process, but the chips are vastly different in scale.

The AMD chip packs 2,080 million transistors on a 160 mm² die, giving a transistor density of 13.0M per mm². The NVIDIA chip has 7,080 million transistors on a 561 mm² die, with a density of 12.6M per mm². The Tesla’s die is 3.5 times larger and holds 3.4 times more transistors, though the density is slightly lower due to the larger area. This explains the Tesla’s higher power draw and compute capability.

The AMD card’s GCN 2.0 architecture brings a newer DirectX feature level (12_0), which is notable for compatibility. The Tesla’s Kepler architecture is older in DirectX terms (11_0), but it compensates with raw compute throughput. Vulkan support is marginally newer on the Tesla (1.2.175 vs 1.2.170). The AMD card is a mobile-oriented part (MXM module), while the Tesla is a workstation accelerator with no display outputs, indicating its purpose is compute-only. The AMD’s "Portable Device Dependent" display outputs confirm it is meant to be paired with a laptop screen or external ports.

Where Each One Wins

The NVIDIA Tesla K20Xm wins in raw compute. The Geekbench OpenCL score of 17,215 is 20% higher than the AMD’s 13,772. For tasks that rely on massive parallel throughput — think scientific simulation, deep learning inference, or video rendering — the Tesla’s 3.935 TFLOPS FP32 rate and 249.6 GB/s bandwidth give it a decisive edge. Its 6 GB VRAM is also a major advantage for datasets that won’t fit in 2 GB. The Tesla’s 2688 shading units and 224 TMUs are purpose-built for workloads that scale with shader count and texture operations.

The AMD Radeon HD 8950M wins in efficiency and versatility. Its 100 W TDP is less than half the Tesla’s 235 W, making it suitable for MXM-based laptops or compact systems. It also has the higher average benchmark score (13,376 vs 12,625) and better percentile ranking (54th vs 52nd). The AMD card’s DirectX 12 (12_0) support is more modern, which could matter for newer games or applications that leverage DX12 features. Its Vulkan score of 12,979 shows it can handle that API well, though no direct comparison is available.

For a user building a stationary compute node with a 550 W PSU, the Tesla is the clear winner. For a mobile workstation or a low-power system, the AMD card is the practical choice. The data shows a trade-off: the Tesla gives you 20% more OpenCL performance and 3x the VRAM, but the AMD gives you a better overall average score, a smaller footprint, and a more modern feature set. Neither card is universally better — the right pick depends entirely on whether you prioritize compute density or system integration.