AMD Radeon HD 7770M vs NVIDIA Tesla K20Xm Comparison

The AMD Radeon HD 7770M and the NVIDIA Tesla K20Xm represent two vastly different philosophies in GPU design: one is a mobile power-sipping chip, the other a dual-slot compute accelerator. While their names suggest a generational gap, the benchmark data reveals a surprising outcome that hinges entirely on the specific workload. The single head-to-head benchmark available shows a clear and decisive winner, but the broader specification sheets tell a story of divergent purposes and capabilities.

Head-to-Head Benchmarks

The only common test between these two GPUs is the Geekbench Metal benchmark, and the results are unequivocal. The AMD Radeon HD 7770M scores 13,536 points, while the NVIDIA Tesla K20Xm manages only 8,035 points. This translates to a deltaPct of -40.6% for the NVIDIA part, meaning the AMD mobile chip outperforms the Tesla compute card by a massive 40.6% in this specific test. This is a remarkable result for a mobile GPU that draws a fraction of the power.

The Tesla K20Xm's score is not just a loss to its rival; it also sits below its nearest rivals in the database. Its average benchmark score of 12,625 places it behind the AMD Radeon RX 7600M XT (avg score 12,710), the NVIDIA GeForce GTX 670 (avg score 12,773), the NVIDIA GeForce GTX 590 (avg score 12,830), and the AMD Radeon Pro 455 (avg score 12,831). The performance gap is narrow, with the closest rival being only 0.7% ahead, but it does rank at the 52nd percentile of all GPUs.

Conversely, the AMD Radeon HD 7770M's score of 13,536 places it just 0.1% behind the AMD Radeon RX 9070 XT, a far more modern and powerful desktop card. It also edges out the NVIDIA GeForce GTX 570 by 0.2% and the NVIDIA P106-090 by 0.5%. Its 54th percentile ranking is higher than the Tesla's, reinforcing that in this particular synthetic workload, the smaller, mobile chip is the more effective performer.

It is critical to note that this is a single data point. The Geekbench Metal test favors the AMD architecture significantly. The data shows a 40.6% lead for the HD 7770M, but this cannot be extrapolated to all workloads. The Tesla K20Xm is built for a different kind of compute, and its strengths will show in other areas, though those are not covered by the direct head-to-head data here.

Architecture Differences

The two GPUs are built on the same 28 nm process node at TSMC, but their internal designs could not be more different. The NVIDIA Tesla K20Xm uses the GK110 chip, part of the Kepler architecture, while the AMD Radeon HD 7770M uses the Chelsea chip, based on GCN 1.0. This fundamental architectural split is the root of their performance divergence.

The most striking difference is in scale. The NVIDIA GK110 is a massive die at 561 mm², housing 7,080 million transistors, resulting in a transistor density of 12.6M / mm². In contrast, the AMD Chelsea is a small chip at just 123 mm², with 1,500 million transistors and a slightly lower density of 12.2M / mm². The Tesla is a giant designed for maximum throughput, while the AMD chip is a compact, efficient design for mobile use.

This scale difference translates directly to core counts. The Tesla K20Xm is equipped with 2,688 shading units, 224 texture mapping units (TMUs), and 48 render output units (ROPs). The HD 7770M has a fraction of that: 512 shading units, 32 TMUs, and 16 ROPs. The Tesla's theoretical peak performance reflects this, with an FP32 rating of 3.935 TFLOPS, a texture rate of 164.0 GTexel/s, and a pixel rate of 40.99 GPixel/s. The AMD chip's figures are 691.2 GFLOPS FP32, 21.60 GTexel/s, and 10.80 GPixel/s, respectively. The NVIDIA card has roughly 5.7 times the raw compute throughput on paper.

Memory configurations continue the theme of disparity. The Tesla K20Xm features 6 GB of GDDR5 memory on a 384-bit bus, delivering a bandwidth of 249.6 GB/s. The HD 7770M has just 1024 MB (1 GB) of GDDR5 on a 128-bit bus, yielding only 64.00 GB/s. The memory clock also differs, with the Tesla running at 1300 MHz (5.2 Gbps effective) and the AMD at 1000 MHz (4 Gbps effective). The Tesla's memory subsystem is designed to feed its massive compute units, while the HD 7770M's is sufficient for its smaller workload.

The feature sets also diverge significantly. The Tesla K20Xm is a compute-focused card with no display outputs, designed for server racks and workstations. It uses a PCIe 3.0 x16 interface and has a TDP of 235 W, requiring a 550 W power supply. The HD 7770M is a mobile part with a TDP of just 32 W, uses PCIe 2.0 x16, and its display outputs are "Portable Device Dependent," meaning they are determined by the laptop it is installed in. The Tesla supports DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175, while the AMD chip supports DirectX 12 (11_1), OpenGL 4.6, and Vulkan 1.2.170. The API support is nearly identical, but the power envelope and physical design could not be more opposed.

Where Each One Wins

Based strictly on the available data, the AMD Radeon HD 7770M wins in the only direct comparison we have. In the Geekbench Metal test, it is 40.6% faster than the NVIDIA Tesla K20Xm. This suggests that for applications that rely on the Metal API, the mobile chip is the clear winner. Its higher average benchmark score and percentile ranking (54 vs 52) corroborate this, indicating it is generally a better performer in database-wide synthetic tests.

The NVIDIA Tesla K20Xm, however, wins in every metric of raw compute capacity. Its FP32 throughput of 3.935 TFLOPS is more than 5.7 times higher than the HD 7770M's 691.2 GFLOPS. Its texture rate (164.0 GTexel/s vs 21.60 GTexel/s) and pixel rate (40.99 GPixel/s vs 10.80 GPixel/s) are similarly dominant. Its memory bandwidth of 249.6 GB/s is almost four times that of the AMD part. For workloads like scientific simulation, deep learning, or high-performance computing that are not reliant on the Metal API, the Tesla's architecture is far more powerful. It is a compute accelerator designed for throughput, not for rendering frames in a synthetic benchmark.

FAQ

Q: Which GPU is faster in the Geekbench Metal benchmark?

A: The AMD Radeon HD 7770M is faster, scoring 13,536 points compared to the NVIDIA Tesla K20Xm's 8,035 points. This represents a 40.6% lead for the AMD part.

Q: How does the NVIDIA Tesla K20Xm compare to its closest rivals?

A: The Tesla K20Xm has an average benchmark score of 12,625. It sits slightly behind the AMD Radeon RX 7600M XT (12,710, -0.7%), NVIDIA GeForce GTX 670 (12,773, -1.2%), NVIDIA GeForce GTX 590 (12,830, -1.6%), and AMD Radeon Pro 455 (12,831, -1.6%).

Q: What are the major differences in raw compute power?

A: The Tesla K20Xm has significantly more processing power. It features 2,688 shading units, 224 TMUs, and 48 ROPs, with an FP32 rating of 3.935 TFLOPS. The HD 7770M has 512 shading units, 32 TMUs, and 16 ROPs, with an FP32 rating of 691.2 GFLOPS.

Q: Which GPU has more memory bandwidth?

A: The NVIDIA Tesla K20Xm has substantially more bandwidth. It uses 6 GB of GDDR5 on a 384-bit bus, achieving 249.6 GB/s. The AMD Radeon HD 7770M has 1024 MB of GDDR5 on a 128-bit bus, providing only 64.00 GB/s.

Q: Are they built on the same manufacturing process?

A: Yes, both GPUs are fabricated by TSMC on a 28 nm process node. However, the Tesla's GK110 die is much larger at 561 mm² compared to the HD 7770M's Chelsea die at 123 mm².

Q: What is the difference in power consumption?

A: The Tesla K20Xm has a TDP of 235 W and is a dual-slot card, while the AMD Radeon HD 7770M has a TDP of just 32 W and is designed for mobile devices.

Specification Differences

| Specification | NVIDIA Tesla K20Xm | AMD Radeon HD 7770M |

| :--- | :--- | :--- |

| Chip | GK110 | Chelsea |

| Architecture | Kepler | GCN 1.0 |

| Generation | Tesla Kepler (Kxx) | London (HD 7700M) |

| Transistors | 7,080 million | 1,500 million |

| Die Size | 561 mm² | 123 mm² |

| Transistor Density | 12.6M / mm² | 12.2M / mm² |

| Memory Clock | 1300 MHz (5.2 Gbps effective) | 1000 MHz (4 Gbps effective) |

| Memory Size | 6 GB | 1024 MB |

| Memory Bus Width | 384 bit | 128 bit |

| Memory Bandwidth | 249.6 GB/s | 64.00 GB/s |

| Shading Units | 2688 | 512 |

| TMUs | 224 | 32 |

| ROPs | 48 | 16 |

| Pixel Rate | 40.99 GPixel/s | 10.80 GPixel/s |

| Texture Rate | 164.0 GTexel/s | 21.60 GTexel/s |

| FP32 Performance | 3.935 TFLOPS | 691.2 GFLOPS |

| TDP | 235 W | 32 W |

| Bus Interface | PCIe 3.0 x16 | PCIe 2.0 x16 |

| Display Outputs | No outputs | Portable Device Dependent |

| Vulkan Version | 1.2.175 | 1.2.170 |

| Release Date | 2012-11-11 | 2012-04-23 |

| Predecessor | Tesla Fermi | Vancouver |

| Successor | Tesla Maxwell | Solar System |

The Verdict

The data presents a straightforward choice for two different audiences. For anyone running the Geekbench Metal test, the AMD Radeon HD 7770M is the superior product, delivering a 40.6% higher score. Its higher average benchmark score and percentile ranking make it the better performer in this synthetic, API-specific workload. This is the GPU to pick for tasks that are primarily bound by Metal performance.

For anyone needing raw computational throughput, the NVIDIA Tesla K20Xm is the only option. Its FP32 performance of 3.935 TFLOPS dwarfs the HD 7770M's 691.2 GFLOPS. Its massively wider memory bus and larger frame buffer (6 GB vs 1 GB) are designed for data-intensive compute tasks, not for rendering graphics in a benchmark. The Tesla is a dual-slot accelerator with no display outputs, built for a server, while the HD 7770M is a low-power mobile chip. The choice is not about which is "better" but which fits the intended use case. The benchmark shows the AMD wins in one specific test, but the specification sheet shows the NVIDIA is in an entirely different league of compute capability.