GPU Comparison

The AMD Radeon HD 6950 and the NVIDIA RTX A400 represent two vastly different eras of GPU design, separated by over a decade of architectural evolution. The data shows a single common benchmark point, Geekbench OpenCL, where the RTX A400 delivers a score of 22,844 compared to the HD 6950's 6,210, a decisive 72.8% margin in favor of the newer card. However, the comparison extends beyond raw compute, revealing fundamental shifts in process technology, feature sets, and intended workloads that define where each card retains relevance.

Where Each One Wins

The NVIDIA RTX A400 is the clear winner in modern compute and API support, as its benchmark results demonstrate a massive lead in Geekbench OpenCL. Its score of 22,844 places it far ahead of the HD 6950, and its support for DirectX 12 Ultimate, Vulkan 1.4, and OpenGL 4.6 means it is built for contemporary software environments. The RTX A400 also brings dedicated RT cores and tensor cores, enabling hardware-accelerated ray tracing and AI workloads that the older AMD card simply cannot handle. Its active production status and modern PCIe 4.0 x8 interface further cement its position as a card for current and future systems.

The AMD Radeon HD 6950, conversely, wins in the context of its own era and specific legacy scenarios. While it loses the single compute benchmark, its architecture was designed for a time when DirectX 11 was the standard, and it supports DirectX 11.2. The card's 2 GB of GDDR5 memory on a 256-bit bus provides 160.0 GB/s of bandwidth, which is a significantly wider memory path than the RTX A400's 64-bit bus, even though the latter has faster GDDR6 memory. In older DirectX 9 and DirectX 10 workloads, the HD 6950's higher texture rate of 70.40 GTexel/s and pixel rate of 25.60 GPixel/s suggest it could hold its own, though no direct benchmark data exists in the pack to confirm this. The HD 6950 also holds a slight edge in average benchmark score versus its nearest rivals, sitting at 6,210 with a percentile of 36, whereas the RTX A400's average is 6,078 with a percentile of 35, indicating the older card is marginally better positioned among its peers.

Architecture Differences

The architectural gap is vast. The AMD Radeon HD 6950 uses the Cayman chip built on TeraScale 3, a 40 nm process from TSMC, with 2,640 million transistors on a 389 mm² die. This results in a transistor density of 6.8 million per square millimeter, a figure that seems primitive by modern standards. In contrast, the NVIDIA RTX A400 uses the GA107 chip on the Ampere architecture, built on an 8 nm process from Samsung, packing 8,700 million transistors into a smaller 200 mm² die, achieving a density of 43.5 million per square millimeter.

The compute configurations differ fundamentally. The HD 6950 has 1,408 shading units, 88 texture mapping units, and 32 ROPs, which gives it a raw FP32 throughput of 2.253 TFLOPS. The RTX A400, despite having fewer shading units at 768, fewer TMUs at 24, and fewer ROPs at 16, achieves a higher FP32 performance of 2.706 TFLOPS thanks to its higher clock speeds. The RTX A400 also has 6 RT cores and 24 tensor cores, features completely absent from the HD 6950. Memory technology has also evolved: the HD 6950 uses 2 GB of GDDR5, while the RTX A400 uses 4 GB of GDDR6, though the latter's 64-bit bus limits bandwidth to 96.00 GB/s compared to the former's 160.0 GB/s.

API support illustrates the generational shift. The HD 6950 tops out at DirectX 11.2 and OpenGL 4.4, with no Vulkan support listed. The RTX A400 supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4, making it compatible with modern game engines and compute frameworks. The physical design also reflects different priorities: the HD 6950 is a dual-slot, 286 mm long card requiring two 6-pin power connectors and a 550 W power supply, while the RTX A400 is a single-slot, 163 mm card with no power connectors and a 250 W suggested PSU, drawing just 50 W versus the HD 6950's 200 W TDP.

Head-to-Head Benchmarks

The only direct comparison available is the Geekbench OpenCL test, and the result is lopsided. The NVIDIA RTX A400 scores 22,844, while the AMD Radeon HD 6950 scores 6,210. This represents a deltaPct of -72.8% for the AMD card, meaning the RTX A400 is approximately 3.7 times faster in this compute workload. The RTX A400's score is not only higher than the HD 6950's but also places it in a competitive position against its nearest rivals, which include the NVIDIA GeForce MX230 at 6,077 and the Quadro P2000 at 6,049, both of which it beats by significant margins.

For the HD 6950, its score of 6,210 puts it just slightly below the AMD FirePro W600 at 6,223 and the NVIDIA Quadro K620 at 6,282, with deltaPct values of -0.2% and -1.1% respectively. This suggests that in its own performance class, the HD 6950 is competitive with other older workstation cards. However, the absolute gap to the RTX A400 is enormous, highlighting how far GPU compute has progressed. The RTX A400 also has additional benchmark data showing strengths in other areas: it scores 5,983 in Passmark G3D, 2,557 in Passmark GPU Compute, and 899 in Passmark G2D, though no comparable data exists for the HD 6950 in these tests.

FAQ

Q: Which card has higher raw compute performance?

A: The NVIDIA RTX A400 has higher FP32 performance at 2.706 TFLOPS compared to the AMD Radeon HD 6950's 2.253 TFLOPS. In the Geekbench OpenCL test, the RTX A400 scores 22,844 versus 6,210, a 72.8% advantage.

Q: Can the AMD Radeon HD 6950 run modern APIs like Vulkan?

A: No. The HD 6950 supports up to DirectX 11.2 and OpenGL 4.4, with no Vulkan support listed. The RTX A400 supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4.

Q: How do the memory subsystems compare?

A: The HD 6950 has 2 GB of GDDR5 on a 256-bit bus with 160.0 GB/s bandwidth. The RTX A400 has 4 GB of GDDR6 on a 64-bit bus with 96.00 GB/s bandwidth, giving the older card a wider but slower memory path.

Q: What is the power consumption difference?

A: The HD 6950 has a 200 W TDP and requires two 6-pin power connectors, while the RTX A400 has a 50 W TDP and requires no power connectors. The suggested PSU is 550 W for the HD 6950 and 250 W for the RTX A400.

Q: Which card supports hardware ray tracing?

A: Only the NVIDIA RTX A400 supports hardware ray tracing, as it features 6 RT cores. The AMD Radeon HD 6950 has no RT cores listed.

Q: How do the cards compare in their production status?

A: The HD 6950 is end-of-life, released in December 2010, while the RTX A400 is active, released in April 2024. The HD 6950 also has a launch MSRP of 299 USD.

The Verdict

The data unequivocally favors the NVIDIA RTX A400 for any modern workload. Its 72.8% lead in Geekbench OpenCL, higher FP32 performance, support for DirectX 12 Ultimate and Vulkan, and inclusion of RT and tensor cores make it the only viable choice for contemporary applications, AI tasks, or any software that leverages modern graphics APIs. Its drastically lower power draw of 50 W versus 200 W and compact single-slot design also make it far easier to integrate into existing systems.

The AMD Radeon HD 6950, while obsolete for modern use, retains a niche appeal for legacy systems. Its wider 256-bit memory bus and higher texture fill rate of 70.40 GTexel/s compared to the RTX A400's 42.29 GTexel/s could theoretically benefit older DirectX 9 or DirectX 10 games that were optimized for such architectures. Its average benchmark score of 6,210 also places it slightly higher in its own percentile ranking (36) than the RTX A400's 35th percentile, suggesting it is a stronger performer among its immediate peers than the RTX A400 is among its own. For a collector or someone maintaining a period-correct Windows 7-era system, the HD 6950 has historical value, but for anyone seeking actual compute capability, the RTX A400 is the definitive choice.

Specification Differences

| Specification | AMD Radeon HD 6950 | NVIDIA RTX A400 |

|---|---|---|

| Architecture | TeraScale 3 | Ampere |

| Process Node | 40 nm (TSMC) | 8 nm (Samsung) |

| Transistors | 2,640 million | 8,700 million |

| Die Size | 389 mm² | 200 mm² |

| Transistor Density | 6.8M / mm² | 43.5M / mm² |

| Memory Clock | 1250 MHz / 5 Gbps effective | 1500 MHz / 12 Gbps effective |

| Memory Size | 2 GB | 4 GB |

| Memory Type | GDDR5 | GDDR6 |

| Memory Bus Width | 256 bit | 64 bit |

| Memory Bandwidth | 160.0 GB/s | 96.00 GB/s |

| Shading Units | 1408 | 768 |

| TMUs | 88 | 24 |

| ROPs | 32 | 16 |

| RT Cores | None | 6 |

| Tensor Cores | None | 24 |

| Pixel Rate | 25.60 GPixel/s | 28.19 GPixel/s |

| Texture Rate | 70.40 GTexel/s | 42.29 GTexel/s |

| FP32 Performance | 2.253 TFLOPS | 2.706 TFLOPS |

| TDP | 200 W | 50 W |

| Slot Width | Dual-slot | Single-slot |

| Power Connectors | 2x 6-pin | None |

| Suggested PSU | 550 W | 250 W |

| Bus Interface | PCIe 2.0 x16 | PCIe 4.0 x8 |

| Display Outputs | 2x DVI, 1x HDMI 1.4a, 2x mini-DisplayPort 1.2 | 4x mini-DisplayPort 1.4a |

| DirectX Support | 11.2 (11_0) | 12 Ultimate (12_2) |

| OpenGL Support | 4.4 | 4.6 |

| Vulkan Support | None | 1.4 |

| Dimensions | 286 mm x 126 mm x 42 mm | 163 mm x 69 mm |

| Production Status | End-of-life | Active |

| Release Date | 2010-12-13 | 2024-04-15 |

| Launch MSRP | 299 USD | Not listed |