AMD Radeon RX 6600S vs NVIDIA Tesla K20c Comparison

Head-to-Head Benchmarks

The only shared benchmark in the database is Geekbench OpenCL, and the result is decisive. The AMD Radeon RX 6600S scores 66,435, while the NVIDIA Tesla K20c scores 11,479. That gives the AMD part an 82.7% advantage in this test. To put that in perspective, the K20c’s nearest rival is the AMD Radeon Pro 5500M at 11,528, which beats it by just 0.4%. The RX 6600S sits in a different performance class entirely: its nearest rival is the AMD Radeon R9 M275X at 10,582, which the RX 6600S beats by 0.4%, and its next rival, the NVIDIA GeForce GTX 560 Ti at 10,690, trails by 0.6%.

The gap between these two GPUs is not marginal; it is a chasm. In raw compute throughput, the RX 6600S delivers 7.168 TFLOPS FP32, while the K20c manages 3.524 TFLOPS. That is roughly double the compute performance, and the Geekbench result reflects it. The RX 6600S also doubles the pixel throughput at 128.0 GPixel/s versus 36.71 GPixel/s, and its texture rate of 224.0 GTexel/s is 52.6% higher than the K20c’s 146.8 GTexel/s.

Interestingly, the K20c still holds a percentile edge over the RX 6600S in the global database. The Tesla ranks in the 51st percentile among all GPUs, while the Radeon sits at the 49th percentile. That suggests the K20c’s single OpenCL result is more competitive against the broader field, whereas the RX 6600S has multiple benchmark results that drag its average down. The RX 6600S averages 10,629 across all tests, which is lower than its OpenCL score alone, while the K20c’s average is identical to its single score at 11,479.

FAQ

Q: Why does the AMD Radeon RX 6600S score so much higher in Geekbench OpenCL?

A: The RX 6600S has a significant raw compute advantage. It delivers 7.168 TFLOPS FP32 compared to the Tesla K20c’s 3.524 TFLOPS, and its memory bandwidth is higher at 224.0 GB/s versus 208.0 GB/s. The RX 6600S also runs at a boost clock of 2000 MHz, while the K20c has no listed boost clock.

Q: The RX 6600S has fewer shading units. How does it still win?

A: The K20c has 2,496 shading units and 208 TMUs, while the RX 6600S has 1,792 shading units and 112 TMUs. However, the RX 6600S compensates with much higher clocks and a more efficient architecture. Its 2000 MHz boost clock versus the K20c’s unlisted clock, combined with a 7 nm process node versus 28 nm, yields higher throughput per unit.

Q: What is the memory situation on each card?

A: The Tesla K20c has 5 GB of GDDR5 on a 320-bit bus, achieving 208.0 GB/s bandwidth. The RX 6600S has 4 GB of GDDR6 on a 128-bit bus, but achieves 224.0 GB/s bandwidth thanks to faster memory at 14 Gbps effective versus 5.2 Gbps effective.

Q: Which GPU has better API support?

A: The RX 6600S supports DirectX 12 Ultimate (12_2) and Vulkan 1.4, while the K20c only supports DirectX 12 (11_0) and Vulkan 1.2.175. Both support OpenGL 4.6. This means the RX 6600S is more future-proof for modern games and applications.

Q: Are these GPUs still in production?

A: Both are end-of-life products. The Tesla K20c was released on 2012-11-11, and the RX 6600S was released on 2022-01-03. The K20c has a successor (Tesla Maxwell), while the RX 6600S does not list a successor.

Q: What are the power requirements?

A: The Tesla K20c has a 225 W TDP and requires a 550 W power supply, with 1x 6-pin and 1x 8-pin power connectors. The RX 6600S has an 80 W TDP, no power connectors, and no specified PSU requirement, as it is an integrated GPU (IGP) for portable devices.

Where Each One Wins

The AMD Radeon RX 6600S wins the only head-to-head benchmark, and it does so by a wide margin. Its strengths are in raw compute, memory bandwidth, and modern feature support. The 7.168 TFLOPS FP32 performance is more than double the K20c’s 3.524 TFLOPS, and its 224.0 GB/s memory bandwidth edges out the Tesla’s 208.0 GB/s despite a narrower 128-bit bus. The RX 6600S also supports DirectX 12 Ultimate, ray tracing (28 RT cores), and Vulkan 1.4, making it viable for contemporary workloads that leverage these APIs.

The RX 6600S is also dramatically more power-efficient. Its 80 W TDP is less than half the K20c’s 225 W, and it does not require external power connectors. This makes it suitable for thin-and-light laptops or compact systems where space and cooling are limited. The 7 nm process node and 46.7M transistors per mm² density show a modern design that extracts more performance per watt.

The NVIDIA Tesla K20c wins in memory capacity and niche compute scenarios. It has 5 GB of VRAM versus 4 GB on the RX 6600S, which could matter for workloads that require larger working sets. The 320-bit bus provides higher memory parallelism, even if the effective bandwidth is slightly lower. The K20c also has more shading units (2,496 vs 1,792) and more TMUs (208 vs 112), which can help in certain compute tasks that scale with shader count rather than clock speed. Its 561 mm² die size and 7,080 million transistors indicate a large, complex chip that was designed for high-end compute in its era.

The K20c’s single benchmark score of 11,479 places it at the 51st percentile, which is higher than the RX 6600S’s 49th percentile. This is notable because the K20c’s score is competitive with the AMD Radeon Pro 5500M (11,528, -0.4%) and the NVIDIA GeForce GTX 1660 (11,680, -1.7%). In contrast, the RX 6600S’s average score of 10,629 is closer to older or lower-tier cards like the NVIDIA Quadro K2200 (10,761, -1.2%) and the AMD Radeon RX 550X (10,481, +1.4%). This suggests that while the RX 6600S excels in OpenCL, its other benchmark results are mediocre.

Specification Differences

The two GPUs differ in nearly every specification category. The K20c uses a GK110 chip on a 28 nm process, while the RX 6600S uses a Navi 23 chip on a 7 nm process. The K20c has 7,080 million transistors on a 561 mm² die, while the RX 6600S packs 11,060 million transistors onto a much smaller 237 mm² die. Transistor density tells the story: 12.6M per mm² for the K20c versus 46.7M per mm² for the RX 6600S.

Memory configurations are starkly different. The K20c has 5 GB of GDDR5 with a 320-bit bus and 208.0 GB/s bandwidth. The RX 6600S has 4 GB of GDDR6 with a 128-bit bus and 224.0 GB/s bandwidth. Memory clocks are 1300 MHz (5.2 Gbps effective) for the K20c and 1750 MHz (14 Gbps effective) for the RX 6600S.

Compute units differ: the K20c has 2,496 shading units, 208 TMUs, and 40 ROPs. The RX 6600S has 1,792 shading units, 112 TMUs, and 64 ROPs. The RX 6600S adds 28 RT cores, which the K20c lacks entirely. Pixel rate is 36.71 GPixel/s for the K20c versus 128.0 GPixel/s for the RX 6600S. Texture rate is 146.8 GTexel/s versus 224.0 GTexel/s. FP32 performance is 3.524 TFLOPS versus 7.168 TFLOPS, and the RX 6600S supports FP16 at 14.34 TFLOPS (2:1) while the K20c has no FP16 figure.

Power and physical specs are also divergent. The K20c has a 225 W TDP, is dual-slot, requires 1x 6-pin and 1x 8-pin connectors, and a 550 W PSU. The RX 6600S has an 80 W TDP, is an IGP, has no power connectors, and no PSU requirement. The K20c uses PCIe 2.0 x16, while the RX 6600S uses PCIe 4.0 x8. The K20c has no display outputs; the RX 6600S outputs are portable-device dependent. The K20c measures 267 mm in length; the RX 6600S has no listed dimensions.

Architecture Differences

The Tesla K20c is built on NVIDIA’s Kepler architecture, using the GK110 chip. It is part of the Tesla Kepler (Kxx) generation, succeeding Tesla Fermi and preceding Tesla Maxwell. The architecture is designed for compute workloads, with a focus on FP32 throughput and memory bandwidth. The 28 nm TSMC process node was state-of-the-art in 2012, but it is now several generations old. The K20c supports DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175, but it lacks modern features like ray tracing and tensor cores.

The AMD Radeon RX 6600S uses the RDNA 2.0 architecture on the Navi 23 chip. It belongs to the Navi Mobile (RX 6000M) generation, succeeding Polaris Mobile. RDNA 2.0 is a modern gaming architecture that introduces ray tracing support via 28 dedicated RT cores. It also supports DirectX 12 Ultimate (12_2), which includes features like mesh shaders and variable rate shading. The 7 nm TSMC process node allows for higher clock speeds and better power efficiency, as evidenced by the 2000 MHz boost clock and 80 W TDP.

The architectural gap between 2012 and 2022 is stark. The K20c uses a monolithic design with 7,080 million transistors on a large die; the RX 6600S crams 11,060 million transistors into a die less than half the size. The RDNA 2.0 architecture’s higher transistor density enables more features per square millimeter, including RT cores and FP16 support. The K20c has no FP16 capability listed, which limits its usefulness in modern AI or machine learning workloads that rely on reduced precision.

The memory architecture also reflects different design philosophies. The K20c’s 320-bit bus is wide but slow, with GDDR5 memory at 5.2 Gbps effective. The RX 6600S uses a narrower 128-bit bus but compensates with faster GDDR6 at 14 Gbps effective, achieving higher total bandwidth. This is a hallmark of RDNA 2.0’s focus on latency reduction and bandwidth efficiency. The K20c’s larger memory pool (5 GB vs 4 GB) is offset by the RX 6600S’s faster data transfer rates.

The Verdict

The data points to a clear split: the AMD Radeon RX 6600S is the better choice for anyone prioritizing raw performance, modern features, and power efficiency. It wins the only head-to-head benchmark by 82.7%, delivers more than double the FP32 throughput (7.168 TFLOPS vs 3.524 TFLOPS), and supports DirectX 12 Ultimate and ray tracing. Its 80 W TDP makes it suitable for portable devices, and it requires no external power connectors.

The NVIDIA Tesla K20c is the better choice for niche compute tasks that benefit from its larger 5 GB memory pool, 320-bit bus, and higher shading unit count (2,496 vs 1,792). Its 51st percentile ranking is slightly better than the RX 6600S’s 49th, and its single benchmark score is more competitive against its rivals. However, its 225 W TDP, dual-slot design, and lack of display outputs make it impractical for modern consumer use. It is also an older product with limited API support (DirectX 11_0) and no ray tracing.

For gaming or general-purpose computing, the RX 6600S is the obvious pick. Its Geekbench OpenCL score of 66,435 dwarfs the K20c’s 11,479, and its modern architecture ensures compatibility with current software. For legacy compute workloads that require maximum memory capacity or shader count, the K20c remains viable, but it is a product of a bygone era. The RX 6600S is the more versatile and future-proof option, provided the workload fits within its 4 GB memory limit.