AMD Radeon HD 6850 X2 vs NVIDIA GeForce GT 745M Comparison

FAQ

Q: Which GPU has the higher average benchmark score?

A: The AMD Radeon HD 6850 X2 has an average benchmark score of 3977, while the NVIDIA GeForce GT 745M scores 3953. The AMD part leads by 0.6%, a margin that places both cards in the same performance tier.

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

A: The AMD Radeon HD 6850 X2 scores 3977 against the NVIDIA GeForce GT 745M's 3580, giving AMD an 11.1% advantage in this specific compute workload.

Q: What is the transistor density difference between the two architectures?

A: Despite using an older 40 nm process, the AMD Radeon HD 6850 X2 packs 1,700 million transistors on a 255 mm² die, yielding 6.7M transistors per mm². The NVIDIA GeForce GT 745M uses a 28 nm process with 1,270 million transistors on 118 mm², achieving 10.8M transistors per mm².

Q: Which GPU supports more modern APIs?

A: The NVIDIA GeForce GT 745M supports DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175. The AMD Radeon HD 6850 X2 supports DirectX 11.2 (11_0) and OpenGL 4.4 but has no Vulkan support listed.

Q: What are the power consumption figures for each card?

A: The AMD Radeon HD 6850 X2 has a TDP of 254 W and requires a 600 W suggested PSU with dual 8-pin connectors. The NVIDIA GeForce GT 745M has a 45 W TDP, uses no power connectors, and has no suggested PSU listed.

Q: What is the memory bandwidth difference?

A: The AMD Radeon HD 6850 X2 delivers 134.4 GB/s over a 256-bit bus, while the NVIDIA GeForce GT 745M provides 64.00 GB/s over a 128-bit bus. The AMD card offers more than double the bandwidth.

Architecture Differences

The AMD Radeon HD 6850 X2 is built on TeraScale 2 architecture using the Barts chip, part of the Northern Islands (HD 6800) generation. It is manufactured on a 40 nm process at TSMC, with 1,700 million transistors on a 255 mm² die. The NVIDIA GeForce GT 745M uses the Kepler architecture with the GK107 chip, belonging to the GeForce 700M generation, and is also fabricated by TSMC but on a smaller 28 nm node, housing 1,270 million transistors on a 118 mm² die.

The architectural lineage diverges significantly. AMD's part is a desktop dual-GPU solution from 2011, while NVIDIA's is a mobile integrated GPU from 2013. The AMD card is a dual-slot design with 2x 8-pin power connectors, whereas the GT 745M is an IGP (integrated graphics processor) with no power connectors, reflecting its mobile orientation.

Compute resources differ sharply. The AMD Radeon HD 6850 X2 has 960 shading units, 48 texture mapping units (TMUs), and 32 raster operation units (ROPs). The NVIDIA GeForce GT 745M has 384 shading units, 32 TMUs, and 16 ROPs. This gives AMD a 2.5x advantage in shading units and a 3x advantage in TMUs, though the architectural efficiency of Kepler partially compensates in certain workloads.

Memory subsystems also differ. Both cards use 2 GB of GDDR5 memory, but AMD's implementation uses a 256-bit bus with 134.4 GB/s bandwidth, while NVIDIA's uses a 128-bit bus with 64.00 GB/s. The AMD card's memory clock is 1050 MHz (4.2 Gbps effective), compared to NVIDIA's 1000 MHz (4 Gbps effective).

The NVIDIA card has a clear API advantage. It supports DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175, while the AMD card tops out at DirectX 11.2 (11_0) and OpenGL 4.4 with no Vulkan support. However, the AMD card's pixel rate of 25.60 GPixel/s and texture rate of 38.40 GTexel/s dwarf NVIDIA's 4.392 GPixel/s and 17.57 GTexel/s, indicating massive fillrate advantages.

Head-to-Head Benchmarks

The only direct benchmark comparison available is the Geekbench OpenCL test, and it favors the AMD Radeon HD 6850 X2 decisively. AMD scores 3977 against NVIDIA's 3580, a delta of 11.1%. This result is consistent with the AMD card's larger compute footprint — 960 shading units versus 384, and 1.536 TFLOPS FP32 performance versus 421.6 GFLOPS.

The 11.1% gap in OpenCL is notable because it is larger than the 0.6% difference in average benchmark scores. This suggests the AMD card's advantage is more pronounced in compute-heavy workloads than in the aggregated score, which likely includes other test types where NVIDIA's Kepler efficiency narrows the gap.

Looking at the nearest rivals for each card provides context. The AMD Radeon HD 6850 X2 sits 0.3% above the NVIDIA Quadro K2000 (3964), 0.5% above the GeForce 830M (3957), and 0.5% above the Radeon R5 M420 (3956). The NVIDIA GeForce GT 745M is 0.1% below the Radeon R5 M420, 0.1% below the GeForce 830M, 0.3% below the Quadro K2000, and 0.6% above the Quadro 2000D (3930). Both cards cluster tightly within a 1% band of their nearest competitors.

In the head-to-head comparison, AMD wins the sole benchmark, giving them 1 win against NVIDIA's 0. The percentile ranking reinforces this: the AMD card sits at the 24th percentile of all GPUs, while the NVIDIA card is at the 23rd percentile. These are effectively equivalent positions, separated by a single percentile point.

Specification Differences

The following fields differ between the AMD Radeon HD 6850 X2 and NVIDIA GeForce GT 745M:

• Architecture: TeraScale 2 vs Kepler
• Chip: Barts vs GK107
• Generation: Northern Islands (HD 6800) vs GeForce 700M
• Process Node: 40 nm vs 28 nm
• Transistors: 1,700 million vs 1,270 million
• Die Size: 255 mm² vs 118 mm²
• Transistor Density: 6.7M / mm² vs 10.8M / mm²
• Memory Clock: 1050 MHz (4.2 Gbps effective) vs 1000 MHz (4 Gbps effective)
• Memory Bus Width: 256 bit vs 128 bit
• Memory Bandwidth: 134.4 GB/s vs 64.00 GB/s
• Shading Units: 960 vs 384
• TMUs: 48 vs 32
• ROPs: 32 vs 16
• Pixel Rate: 25.60 GPixel/s vs 4.392 GPixel/s
• Texture Rate: 38.40 GTexel/s vs 17.57 GTexel/s
• FP32 Performance: 1.536 TFLOPS vs 421.6 GFLOPS
• TDP: 254 W vs 45 W
• Slot Width: Dual-slot vs IGP
• Power Connectors: 2x 8-pin vs None
• Suggested PSU: 600 W vs None
• Bus Interface: PCIe 2.0 x16 vs PCIe 3.0 x16
• Display Outputs: 2x DVI, 1x HDMI 1.3a, 1x DisplayPort 1.1 vs Portable Device Dependent
• DirectX Support: 11.2 (11_0) vs 12 (11_0)
• OpenGL Support: 4.4 vs 4.6
• Vulkan Support: None vs 1.2.175
• Release Date: 2011-09-18 vs 2013-03-31
• Predecessor: Evergreen vs GeForce 600M
• Successor: Southern Islands vs GeForce 800M

Both cards share 2 GB GDDR5 memory, TSMC as foundry, no RT cores, no tensor cores, no FP16 support, and end-of-life production status.

Where Each One Wins

The AMD Radeon HD 6850 X2 wins in raw compute throughput. Its 1.536 TFLOPS FP32 performance is 3.6x higher than the NVIDIA card's 421.6 GFLOPS, and its shading unit count of 960 is 2.5x greater. The pixel rate of 25.60 GPixel/s and texture rate of 38.40 GTexel/s represent fillrate advantages of 5.8x and 2.2x respectively. In the Geekbench OpenCL test, AMD leads by 11.1%, confirming that compute-heavy workloads favor this card. Its 256-bit memory bus and 134.4 GB/s bandwidth provide over double the memory throughput.

The NVIDIA GeForce GT 745M wins in efficiency and platform compatibility. Its 45 W TDP is a fraction of AMD's 254 W, making it suitable for mobile devices where power constraints are critical. It supports PCIe 3.0 x16 versus AMD's PCIe 2.0 x16, offering double the bus bandwidth. The NVIDIA card also has superior API support, including DirectX 12, OpenGL 4.6, and Vulkan 1.2.175, which the AMD card lacks entirely. Its 28 nm process node with 10.8M transistors per mm² demonstrates significantly higher transistor density, reflecting a more modern manufacturing approach.

The average benchmark scores tell a nuanced story. AMD's average of 3977 is only 0.6% above NVIDIA's 3953, indicating that the GT 745M's architectural efficiency partially compensates for its smaller compute resources. In the nearest rival comparison, both cards are surrounded by identical competitors — the Quadro K2000, GeForce 830M, and Radeon R5 M420 — suggesting they occupy the same performance class despite their different designs.

The Verdict

The data shows a clear split between these two GPUs: AMD wins on raw performance, NVIDIA wins on efficiency and modern feature support. In the only direct benchmark, the AMD Radeon HD 6850 X2 outperforms the NVIDIA GeForce GT 745M by 11.1% in OpenCL compute, a meaningful margin that reflects its 3.6x FP32 advantage and 2.5x shading unit count.

However, the overall benchmark averages tell a different story. The AMD card's average score of 3977 is merely 0.6% higher than NVIDIA's 3953, and both cards sit at the 24th and 23rd percentiles of all GPUs respectively. This suggests that in a broader range of workloads, the Kepler architecture's efficiency narrows the gap substantially.

For a user prioritizing compute performance, fillrate, and memory bandwidth in a desktop environment where power consumption is not a concern, the AMD Radeon HD 6850 X2 is the clear choice. Its 134.4 GB/s bandwidth, 25.60 GPixel/s pixel rate, and 38.40 GTexel/s texture rate are dominant figures that the GT 745M cannot approach.

For a user requiring a mobile solution or modern API support, the NVIDIA GeForce GT 745M is the only viable option. Its 45 W TDP makes it suitable for laptops, and its support for DirectX 12, Vulkan 1.2.175, and OpenGL 4.6 ensures compatibility with contemporary software. The PCIe 3.0 interface is another modern advantage.

The production timelines reinforce this split: AMD's card launched in 2011 and is end-of-life, while NVIDIA's launched in 2013 and is also end-of-life. Both are legacy products, but the NVIDIA card benefits from a more recent design and smaller process node.

The verdict depends entirely on use case. For desktop compute tasks where power is available and performance is paramount, the AMD Radeon HD 6850 X2 delivers superior results in the benchmark data. For mobile use or applications requiring modern API support, the NVIDIA GeForce GT 745M is the appropriate selection despite its lower raw performance. The 0.6% average score difference means neither card offers a statistically significant overall advantage; the decision rests on the specific workload and platform requirements.