AMD Radeon HD 6950 vs NVIDIA GeForce 840M Comparison

AMD Radeon HD 6950 vs NVIDIA GeForce 840M: the data compares a 2010 desktop flagship against a 2014 mobile chip. The AMD card wins the only shared benchmark, but the story is more complex than a single score. The HD 6950 holds a 7.7% lead in Geekbench OpenCL (6210 vs 5764), while the 840M counters with a Vulkan score of 4880, a test the AMD card cannot run. The HD 6950 sits at the 36th percentile of all GPUs, the 840M at the 31st. These are close overall positions, but the architectures serve completely different purposes.

Where Each One Wins

The AMD Radeon HD 6950 wins in raw compute throughput. Its Geekbench OpenCL score of 6210 beats the 840M's 5764 by 7.7%, and its FP32 output of 2.253 TFLOPS dwarfs the mobile chip's 863.2 GFLOPS. The HD 6950 also wins decisively on memory bandwidth: 160.0 GB/s versus 16.02 GB/s, a tenfold gap. Pixel rate favors the desktop card at 25.60 GPixel/s versus 8.992 GPixel/s, and texture rate is 70.40 GTexel/s versus 17.98 GTexel/s. For any workload that stresses shader throughput, fill rate, or memory bandwidth, the HD 6950 is the clear choice.

The NVIDIA GeForce 840M wins on portability and efficiency. Its TDP is 33 W versus 200 W, it needs no power connectors, and it is an IGP (integrated graphics package) rather than a dual-slot card. The 840M also supports Vulkan 1.4, while the HD 6950 has no Vulkan support listed. Its Geekbench Vulkan score of 4880 is the only benchmark in the database where the 840M produces a result the HD 6950 cannot match. The 840M also carries newer API support: DirectX 12 (11_0) versus DirectX 11.2 (11_0), and OpenGL 4.6 versus 4.4. In a modern software environment that favors Vulkan, the 840M has a functional advantage despite lower raw compute.

Architecture Differences

The HD 6950 uses the Cayman chip built on TeraScale 3, a 40 nm design from TSMC. It packs 2,640 million transistors on a 389 mm² die, with a transistor density of 6.8M per mm². The 840M uses GM108S on the Maxwell architecture, a 28 nm TSMC part with 1,020 million transistors on a 77 mm² die, density of 13.2M per mm². The HD 6950 is the larger, older, more power-hungry design; the 840M is smaller, denser, and far more efficient.

Shading resources differ massively. The HD 6950 has 1408 shading units, 88 TMUs, and 32 ROPs. The 840M has 384 shading units, 16 TMUs, and 8 ROPs. The desktop card runs its memory at 1250 MHz (5 Gbps effective) across a 256 bit bus with GDDR5; the mobile chip uses 1001 MHz (2 Gbps effective) on a 64 bit bus with DDR3. The HD 6950's memory subsystem is simply in another class. The 840M's base clock is 1029 MHz with a boost of 1124 MHz; the HD 6950 has no base or boost clock listed in the database, only its memory clock. Feature-wise, the 840M supports Vulkan 1.4, DirectX 12 (11_0), and OpenGL 4.6, while the HD 6950 is limited to DirectX 11.2 (11_0) and OpenGL 4.4 with no Vulkan. The HD 6950 uses PCIe 2.0 x16; the 840M uses PCIe 3.0 x8. The desktop card needs a 550 W suggested PSU and dual-slot spacing with 2x 6-pin connectors; the 840M draws power from the portable device itself.

FAQ

Q: Which GPU has the higher Geekbench OpenCL score?

A: The AMD Radeon HD 6950 scores 6210, which is 7.7% higher than the NVIDIA GeForce 840M's 5764.

Q: Can the AMD Radeon HD 6950 run Vulkan workloads?

A: No. The database lists no Vulkan support for the HD 6950. The NVIDIA GeForce 840M supports Vulkan 1.4 and has a Geekbench Vulkan score of 4880.

Q: How do the memory bandwidth figures compare?

A: The HD 6950 has 160.0 GB/s of bandwidth from 2 GB GDDR5 on a 256 bit bus. The 840M has 16.02 GB/s from 2 GB DDR3 on a 64 bit bus. That is a tenfold difference in favor of the AMD card.

Q: Which GPU consumes less power?

A: The NVIDIA GeForce 840M has a 33 W TDP and requires no power connectors. The AMD Radeon HD 6950 has a 200 W TDP, is dual-slot, and requires 2x 6-pin power connectors plus a 550 W suggested PSU.

Q: What is the transistor density difference?

A: The 840M's GM108S die has a density of 13.2M transistors per mm². The HD 6950's Cayman die has 6.8M per mm². The 840M is built on a 28 nm process versus 40 nm for the HD 6950.

Q: Which GPU has better pixel and texture fill rates?

A: The HD 6950 leads with 25.60 GPixel/s and 70.40 GTexel/s. The 840M trails with 8.992 GPixel/s and 17.98 GTexel/s.

Specification Differences

| Specification | AMD Radeon HD 6950 | NVIDIA GeForce 840M |

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

| Architecture | TeraScale 3 | Maxwell |

| Process Node | 40 nm | 28 nm |

| Transistors | 2,640 million | 1,020 million |

| Die Size | 389 mm² | 77 mm² |

| Transistor Density | 6.8M / mm² | 13.2M / mm² |

| Base Clock | None listed | 1029 MHz |

| Boost Clock | None listed | 1124 MHz |

| Memory Clock | 1250 MHz, 5 Gbps effective | 1001 MHz, 2 Gbps effective |

| Memory Type | GDDR5 | DDR3 |

| Memory Bus Width | 256 bit | 64 bit |

| Memory Bandwidth | 160.0 GB/s | 16.02 GB/s |

| Shading Units | 1408 | 384 |

| TMUs | 88 | 16 |

| ROPs | 32 | 8 |

| Pixel Rate | 25.60 GPixel/s | 8.992 GPixel/s |

| Texture Rate | 70.40 GTexel/s | 17.98 GTexel/s |

| FP32 | 2.253 TFLOPS | 863.2 GFLOPS |

| TDP | 200 W | 33 W |

| Slot Width | Dual-slot | IGP |

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

| Suggested PSU | 550 W | None listed |

| Bus Interface | PCIe 2.0 x16 | PCIe 3.0 x8 |

| Display Outputs | 2x DVI, 1x HDMI 1.4a, 2x mini-DisplayPort 1.2 | Portable Device Dependent |

| DirectX | 11.2 (11_0) | 12 (11_0) |

| OpenGL | 4.4 | 4.6 |

| Vulkan | None listed | 1.4 |

| Release Date | 2010-12-13 | 2014-03-11 |

| Launch MSRP | 299 USD | None listed |

Head-to-Head Benchmarks

The only direct benchmark shared by both GPUs is Geekbench OpenCL. The AMD Radeon HD 6950 scores 6210, and the NVIDIA GeForce 840M scores 5764. The delta is 7.7% in favor of AMD. That margin is modest in absolute terms, but it is consistent with the hardware gap: the HD 6950 has 3.7 times the shading units, 5.5 times the TMUs, 4 times the ROPs, and roughly 2.6 times the FP32 throughput. The OpenCL test appears to be memory and shader bound, which is exactly where the HD 6950 dominates with its 256 bit GDDR5 interface and 160.0 GB/s bandwidth.

The 840M's counterpoint is its Vulkan score of 4880. Since the HD 6950 has no Vulkan support, this is not a head-to-head comparison, but it is the only recorded benchmark where the 840M produces a usable result that the AMD card cannot. The 840M also supports DirectX 12 (11_0), while the HD 6950 is limited to DirectX 11.2 (11_0). A modern game or compute application that uses Vulkan or DirectX 12 features will simply not run on the HD 6950, regardless of its raw compute lead. The 840M's 33 W TDP and IGP form factor also make it usable in thin laptops, while the HD 6950 requires a full desktop slot, dual-slot cooling, and a 550 W PSU.

Looking at the rivals list, the HD 6950's 6210 OpenCL score places it within 1.1% of the NVIDIA Quadro K620 (6282) and 0.2% of the AMD FirePro W600 (6223). The 840M's 5764 OpenCL score sits 0.7% above the NVIDIA GeForce 940M (5284 is the listed rival, but the delta is 0.7% against a different entry; the closest rival is the GeForce 930A at 5317, with a 0.1% delta). The 840M's average benchmark score of 5322 is dragged down by its Vulkan result, but its OpenCL score alone is only 7.7% behind a desktop card with vastly more silicon.

The Verdict

Choose the AMD Radeon HD 6950 if you need the highest compute throughput and have the power budget. The data shows a 7.7% OpenCL lead, 2.253 TFLOPS FP32, 160.0 GB/s memory bandwidth, and fill rates of 25.60 GPixel/s and 70.40 GTexel/s. This is the card for shader-heavy workloads, high-resolution texture streaming, and any task that saturates memory bandwidth. Its 36th percentile ranking versus the 840M's 31st also reflects a higher overall standing in the database. It is a dual-slot, 200 W desktop card with a 299 USD launch MSRP, so it belongs in a stationary system with a 550 W PSU.

Choose the NVIDIA GeForce 840M if you need portability, modern API support, or low power draw. Its 33 W TDP, IGP slot width, and lack of power connectors make it the only realistic choice for a laptop. The Vulkan 1.4 support and DirectX 12 (11_0) mean it can run software that the HD 6950 cannot even launch. Its OpenCL score of 5764 is only 7.7% behind a card with 2,640 million transistors, which speaks to the efficiency of Maxwell on 28 nm. The 840M's 4880 Vulkan score is its own niche: if your application uses Vulkan, the HD 6950 is not an option at all.

The verdict is not about which is "better" in the abstract. The HD 6950 wins every performance metric that both GPUs can execute, and it wins them by wide margins in memory bandwidth and fill rate. The 840M wins on compatibility, efficiency, and portability. For a desktop builder with a strong PSU and no need for Vulkan, the HD 6950 is the obvious pick. For a laptop user or anyone running Vulkan-based software, the 840M is the only one of these two that will work. The database records one shared benchmark, and the AMD card takes it, but the 840M's API support gives it a lifespan advantage that raw scores cannot capture.