NVIDIA GeForce GTX 1080 vs NVIDIA Tesla K20c Comparison

# The Verdict

The data in this comparison is unusually one-sided. The NVIDIA GeForce GTX 1080 leads the NVIDIA Tesla K20c in every benchmark category where both have results, with a single head-to-head benchmark showing a 346.1% advantage for the GTX 1080 in Geekbench OpenCL. The GTX 1080 also edges out the Tesla K20c on average benchmark score, posting 11960 versus 11479. If you are choosing between these two for any workload that relies on raw compute performance, the GTX 1080 is the clear pick.

The Tesla K20c, despite being a professional compute card, shows its age. Its only benchmark result, Geekbench OpenCL at 11479, places it in the same percentile as the GTX 1080 (both at 51st percentile), but that percentile is misleading — the GTX 1080 achieves that standing with nearly 4.5 times the OpenCL score. The Tesla K20c's nearest rivals include the AMD Radeon Pro 5500M (deltaPct -0.4%) and the AMD Radeon RX 7800 XT (deltaPct -1.3%), meaning it sits just behind those cards. Meanwhile, the GTX 1080's nearest rivals are the NVIDIA GeForce GTX 960A (deltaPct -0.3%) and the AMD Radeon RX 6500 XT (deltaPct 1%), showing it competes with a much newer generation of hardware.

For a builder today, the choice is straightforward: pick the GTX 1080 for gaming, general compute, and any workload where driver support and API compatibility matter. The Tesla K20c offers no display outputs, making it unsuitable for any desktop use case. It is a compute-only accelerator with a PCIe 2.0 interface, while the GTX 1080 uses PCIe 3.0 x16. The Tesla K20c's launch MSRP was 3,199 USD, but that is historical context; the benchmark data shows it cannot keep pace with the GTX 1080, which had a launch MSRP of 599 USD.

FAQ

Q: Which card has a higher average benchmark score?

A: The NVIDIA GeForce GTX 1080 scores 11960 on average, while the NVIDIA Tesla K20c scores 11479. That is a difference of 481 points, or roughly 4.2% in favor of the GTX 1080.

Q: How do the two cards compare in the Geekbench OpenCL test?

A: The GTX 1080 scores 51204, while the Tesla K20c scores 11479. This gives the GTX 1080 a 346.1% advantage in the head-to-head comparison, making it the outright winner of that benchmark.

Q: What are the nearest rivals to each card?

A: The GTX 1080's closest competitor is the NVIDIA GeForce GTX 960A, which scores 11998 (deltaPct -0.3%). The Tesla K20c's closest rival is the AMD Radeon Pro 5500M, scoring 11528 (deltaPct -0.4%). Both cards sit near the 51st percentile of all GPUs.

Q: Can the Tesla K20c be used for display output?

A: No. The Tesla K20c has no display outputs listed in its specifications. The GTX 1080, by contrast, offers 1x DVI, 1x HDMI 2.0, and 3x DisplayPort 1.4a outputs.

Q: Which card supports newer PCIe and API standards?

A: The GTX 1080 uses PCIe 3.0 x16 and supports DirectX 12 (12_1), OpenGL 4.6, and Vulkan 1.4. The Tesla K20c uses PCIe 2.0 x16 and supports DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175.

Q: What is the transistor count difference between the two?

A: The GTX 1080 has 7,200 million transistors on a 314 mm² die, while the Tesla K20c has 7,080 million transistors on a 561 mm² die. The GTX 1080 achieves a much higher transistor density at 22.9M per mm² versus 12.6M per mm².

Architecture Differences

The two cards come from entirely different NVIDIA architectures and process nodes. The GTX 1080 is built on the Pascal architecture using the GP104 chip, fabricated on a 16 nm process at TSMC. The Tesla K20c uses the Kepler architecture with the GK110 chip, also from TSMC but on a 28 nm process. This process shrink is the primary driver of the GTX 1080's efficiency advantage: it fits 7,200 million transistors into a 314 mm² die, while the Tesla K20c needs 561 mm² to house its 7,080 million transistors. The transistor density tells the story — 22.9M per mm² for the GTX 1080 versus 12.6M per mm² for the Tesla K20c.

Memory technology also differs fundamentally. The GTX 1080 uses 8 GB of GDDR5X memory with a 256-bit bus, achieving 320.3 GB/s of bandwidth. The Tesla K20c uses 5 GB of GDDR5 on a 320-bit bus, yielding 208.0 GB/s. Despite having a wider memory bus, the older GDDR5 memory and lower effective clock speed (5.2 Gbps versus 10 Gbps) hold the Tesla K20c back.

Feature support reflects the architectural gap. The GTX 1080 supports DirectX 12 (12_1) and Vulkan 1.4, while the Tesla K20c supports DirectX 12 (11_0) and Vulkan 1.2.175. Both support OpenGL 4.6. The GTX 1080 also includes modern display outputs, while the Tesla K20c has none — it is a compute-only accelerator by design. The Tesla K20c's generation is listed as "Tesla Kepler (Kxx)" with a predecessor of "Tesla Fermi" and successor "Tesla Maxwell," placing it in NVIDIA's professional compute line. The GTX 1080 belongs to the GeForce 10-series, succeeding GeForce 900 and preceding GeForce 20.

Specification Differences

The clock speeds differ sharply. The GTX 1080 has a base clock of 1607 MHz and a boost clock of 1733 MHz. The Tesla K20c has no base or boost clock listed in the data. Memory clocks also diverge: the GTX 1080 runs at 1251 MHz with 10 Gbps effective, while the Tesla K20c runs at 1300 MHz with 5.2 Gbps effective.

Shading unit counts are close — 2560 for the GTX 1080 versus 2496 for the Tesla K20c — but the texture and pixel rates are not. The GTX 1080 posts 277.3 GTexel/s and 110.9 GPixel/s, while the Tesla K20c manages 146.8 GTexel/s and 36.71 GPixel/s. The FP32 compute performance is a major differentiator: 8.873 TFLOPS for the GTX 1080 versus 3.524 TFLOPS for the Tesla K20c. The GTX 1080 also lists FP16 performance at 138.6 GFLOPS (1:64), while the Tesla K20c has no FP16 figure.

Power delivery and system requirements follow the performance gap. The GTX 1080 has a TDP of 180 W with a single 8-pin power connector and a suggested PSU of 450 W. The Tesla K20c draws 225 W, requires a 6-pin plus an 8-pin connector, and suggests a 550 W PSU. Both are dual-slot cards of identical length (267 mm / 10.5 inches), but the GTX 1080 has full dimensions listed (112 mm height, 40 mm width), while the Tesla K20c lists only length.

Release dates show the generational gap: the GTX 1080 launched on 2016-05-26, while the Tesla K20c launched on 2012-11-11. Both are end-of-life products. The GTX 1080's bus interface is PCIe 3.0 x16 versus PCIe 2.0 x16 for the Tesla K20c.

Head-to-Head Benchmarks

Only one benchmark is shared between the two cards: Geekbench OpenCL. The GTX 1080 scores 51204, and the Tesla K20c scores 11479. This is a deltaPct of 346.1% in favor of the GTX 1080. To put that in perspective, the Tesla K20c would need to more than quadruple its score to match the GTX 1080.

The GTX 1080 also holds the advantage in average benchmark score, 11960 versus 11479. That gap of 481 points is modest compared to the OpenCL delta, but it reflects the fact that the GTX 1080 has 11 benchmark results spanning DirectX 9 through 12, Metal, OpenCL, Vulkan, and 2D/3D tests, while the Tesla K20c has only the single OpenCL result. The GTX 1080's individual scores range from 55 in Passmark DirectX 12 to 51204 in Geekbench OpenCL, with a Passmark G3D score of 15586 and a Geekbench Metal score of 23824.

For the Tesla K20c, the lack of any other benchmark results means its aggregate performance cannot be fully assessed. Its single OpenCL score of 11479 places it at the 51st percentile of all GPUs, which is the same percentile as the GTX 1080 — but the GTX 1080 achieves that percentile with far more consistent performance across a broader range of tests.

Where Each One Wins

The GTX 1080 wins everywhere the data allows comparison. In the single head-to-head benchmark, it wins outright with a 346.1% OpenCL advantage. It wins on average benchmark score by 4.2%. It wins on FP32 compute (8.873 TFLOPS versus 3.524 TFLOPS), on pixel rate (110.9 GPixel/s versus 36.71 GPixel/s), on texture rate (277.3 GTexel/s versus 146.8 GTexel/s), and on memory bandwidth (320.3 GB/s versus 208.0 GB/s). It also wins on efficiency, delivering more performance at a lower TDP (180 W versus 225 W).

For use cases, the GTX 1080 is the practical choice for gaming and general desktop workloads. It has display outputs, supports DirectX 12 (12_1), and has a modern PCIe 3.0 interface. Its 8 GB of GDDR5X memory and 10 Gbps effective speed make it suitable for memory-intensive tasks, and its Passmark G3D score of 15586 indicates strong rasterization performance.

The Tesla K20c has no winning use case based on the data. It is compute-only, with no display outputs, a slower PCIe 2.0 interface, and lower performance across every measurable metric. Its only potential advantage is historical: it launched in 2012 as a Tesla Kepler product, and its 5 GB of GDDR5 memory on a 320-bit bus might have served specific professional compute workloads of that era. But against the GTX 1080, the benchmark results show no scenario where the Tesla K20c comes out ahead. If you need a compute accelerator today, the GTX 1080's OpenCL score alone makes it the only rational choice from this pairing.