AMD Radeon HD 6850 X2 vs NVIDIA Quadro K2100M Comparison

The NVIDIA Quadro K2100M and AMD Radeon HD 6850 X2 represent two very different approaches to GPU design from their respective eras. The data shows a single head-to-head benchmark result, but the specifications reveal stark contrasts in architecture, power, and intended use. The Quadro K2100M, a professional mobile solution from the Kepler generation, edges out the older, dual-GPU desktop behemoth from AMD’s TeraScale 2 era in the one test they share.

Where Each One Wins

The benchmark results indicate a clear, albeit narrow, victory for the NVIDIA Quadro K2100M. In the only common test, Geekbench OpenCL, the Quadro K2100M scores 4587 against the Radeon HD 6850 X2’s 3977. This translates to a 15.3% advantage for NVIDIA. This single win means the Quadro K2100M holds a decisive edge in the available compute metric, suggesting it is better suited for OpenCL-based workloads that the benchmark captures.

However, the Radeon HD 6850 X2 does not win in any recorded benchmark. Its only score comes from that same OpenCL test, where it falls behind. This does not necessarily mean it is without merit in all tasks, but within the data provided, it has no victory to claim. The Quadro K2100M’s win is its sole data point, but it is a significant one, placing it in a different performance tier for general-purpose compute.

The use-case split is therefore defined by the test itself. For users prioritizing OpenCL performance as measured by Geekbench, the Quadro K2100M is the clear choice. The Radeon HD 6850 X2, despite its higher raw specifications in several areas, does not translate that into a benchmark win here. Its strengths may lie in other, unmeasured areas, but the data cannot support a claim of superiority in any tested workload.

Architecture Differences

The architectural divide between these two GPUs is fundamental. The NVIDIA Quadro K2100M is built on the Kepler architecture, using the GK106S chip, and is fabricated on a 28 nm process at TSMC. It packs 2,540 million transistors into a 221 mm² die, achieving a transistor density of 11.5M per mm². In contrast, the AMD Radeon HD 6850 X2 uses the older TeraScale 2 architecture with the Barts chip, built on a larger 40 nm process. This older process results in 1,700 million transistors spread across a larger 255 mm² die, yielding a lower density of 6.7M per mm².

The memory subsystems also differ significantly. Both cards have 2 GB of GDDR5 memory, but the Radeon’s configuration is much wider. It uses a 256-bit bus, delivering a bandwidth of 134.4 GB/s. The Quadro K2100M uses a narrower 128-bit bus, resulting in a bandwidth of just 48.13 GB/s. This is a massive difference in memory throughput, favoring the AMD card by a factor of nearly three.

The compute cores are organized differently as well. The Radeon HD 6850 X2 has 960 shading units and 32 ROPs, while the Quadro K2100M has only 576 shading units and 16 ROPs. Both have 48 TMUs. The Radeon’s higher shading unit count contributes to its higher theoretical fill rates, with a pixel rate of 25.60 GPixel/s and a texture rate of 38.40 GTexel/s, compared to the Quadro’s 8.004 GPixel/s and 32.02 GTexel/s. The FP32 performance also favors AMD, with 1.536 TFLOPS versus 768.4 GFLOPS for NVIDIA.

Power consumption is where the design philosophies diverge most sharply. The Quadro K2100M is a mobile, MXM Module with a TDP of just 55 W and no power connectors. The Radeon HD 6850 X2 is a dual-slot desktop card with a TDP of 254 W, requiring two 8-pin power connectors and a suggested 600 W power supply. This makes the Quadro suitable for portable workstations, while the Radeon demands a substantial desktop chassis and power delivery system.

Head-to-Head Benchmarks

The only direct comparison available is the Geekbench OpenCL test. In this benchmark, the NVIDIA Quadro K2100M scores 4587, while the AMD Radeon HD 6850 X2 scores 3977. The winner is the Quadro K2100M, with a delta of 15.3%.

This result is notable because the Radeon HD 6850 X2 has significantly higher theoretical specifications. Its FP32 performance is exactly double that of the Quadro (1.536 TFLOPS vs 768.4 GFLOPS), and its memory bandwidth is nearly triple (134.4 GB/s vs 48.13 GB/s). Despite these advantages, it loses in the OpenCL benchmark. This suggests that the Kepler architecture’s efficiency and driver optimization for compute workloads outweigh the raw hardware advantages of the older TeraScale 2 design in this specific test.

The 15.3% margin is substantial. It is not a close call. The data indicates that for OpenCL workloads, the Quadro K2100M is clearly the more capable processor. The Radeon’s higher fill rates and shading unit count do not translate into a win here, highlighting that architectural efficiency can be more important than raw specifications in real-world compute benchmarks.

Specification Differences

The two cards differ in nearly every major specification category. The most obvious difference is in the process node, with the Quadro K2100M using a 28 nm process versus the Radeon’s 40 nm. This leads to the Quadro having a higher transistor density (11.5M / mm² vs 6.7M / mm²) despite having fewer total transistors (2,540 million vs 1,700 million) and a smaller die (221 mm² vs 255 mm²).

Clock speeds are another area of divergence. The Quadro K2100M has a fixed base and boost clock of 667 MHz. The Radeon HD 6850 X2 does not have a listed base or boost clock, only a memory clock of 1050 MHz (4.2 Gbps effective), compared to the Quadro’s 752 MHz (3 Gbps effective). The Radeon’s memory clock is higher, but its bus width is the primary driver of its bandwidth advantage.

The shading unit and ROP counts differ, with the Radeon having 960 shading units and 32 ROPs to the Quadro’s 576 and 16, respectively. The TDP is a major differentiator, with the Radeon drawing 254 W compared to the Quadro’s 55 W. The form factor also differs, with the Quadro being an MXM Module and the Radeon being a Dual-slot card. The Radeon requires 2x 8-pin power connectors and a 600 W PSU, while the Quadro uses none.

API support is also distinct. The Quadro K2100M supports DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175. The Radeon HD 6850 X2 supports DirectX 11.2 (11_0) and OpenGL 4.4, but has no Vulkan support. The bus interfaces differ, with the Quadro using MXM-A (3.0) and the Radeon using PCIe 2.0 x16. Finally, the display outputs are different, with the Radeon offering 2x DVI, 1x HDMI 1.3a, and 1x DisplayPort 1.1, while the Quadro’s outputs are listed as "Portable Device Dependent."

FAQ

Q: Which GPU has a higher average benchmark score?

A: The NVIDIA Quadro K2100M has an average benchmark score of 4151, while the AMD Radeon HD 6850 X2 has an average score of 3977.

Q: How much faster is the NVIDIA Quadro K2100M in the Geekbench OpenCL test?

A: The Quadro K2100M scores 4587 compared to the Radeon’s 3977, a 15.3% advantage.

Q: What is the TDP difference between the two cards?

A: The AMD Radeon HD 6850 X2 has a TDP of 254 W, while the NVIDIA Quadro K2100M has a TDP of 55 W.

Q: Which GPU has a wider memory bus?

A: The AMD Radeon HD 6850 X2 uses a 256-bit bus, while the NVIDIA Quadro K2100M uses a 128-bit bus.

Q: Does the AMD Radeon HD 6850 X2 support Vulkan?

A: No, the Radeon HD 6850 X2 has no Vulkan support listed, while the Quadro K2100M supports Vulkan 1.2.175.

Q: What is the transistor count for each GPU?

A: The NVIDIA Quadro K2100M has 2,540 million transistors, and the AMD Radeon HD 6850 X2 has 1,700 million transistors.

The Verdict

From the data, the NVIDIA Quadro K2100M is the better choice for anyone prioritizing OpenCL compute performance. It wins the sole head-to-head benchmark by a significant 15.3% margin, despite having lower theoretical specifications like FP32 performance and memory bandwidth. Its modern Kepler architecture, lower power draw of 55 W, and support for newer APIs like Vulkan make it a more efficient and capable platform for compute tasks.

The AMD Radeon HD 6850 X2, while possessing superior raw specs in terms of shading units, ROPs, and memory bandwidth, fails to convert these into a benchmark victory. Its 254 W TDP and requirement for a 600 W power supply make it a power-hungry option that is less practical for modern systems. Its lack of Vulkan support and older TeraScale 2 architecture further limit its appeal.

The choice is clear for a user focused on the measured OpenCL workload: the Quadro K2100M is the winner. For those who might have hoped the Radeon’s higher fill rates would dominate, the data suggests otherwise. The Quadro’s efficiency and architectural advantages prove decisive in the only test that matters here. The Radeon HD 6850 X2 is a relic of a different era, and the benchmark results confirm that the newer, more efficient NVIDIA design is the superior performer in this comparison.