AMD Radeon R9 M265X vs NVIDIA GeForce GTX 675MX Comparison

Where Each One Wins

The benchmark data splits cleanly between these two mobile graphics processors, but not in the way the raw specifications might suggest. The NVIDIA GeForce GTX 675MX takes the sole head-to-head win in the Geekbench OpenCL test, posting a score of 10,723 against the AMD Radeon R9 M265X's 8,851. That is a 17.5% margin in NVIDIA's favor, and it is the only direct comparison available in the dataset.

The AMD Radeon R9 M265X does not record a single benchmark win in the head-to-head table. Its 8,851 OpenCL score places it at the 44th percentile of all GPUs, while the GTX 675MX's 10,723 OpenCL result puts it at the 43rd percentile. This is a curious outcome: the AMD card ranks one percentile point higher overall despite losing the direct comparison by a wide margin. The explanation lies in the rival sets. The R9 M265X's nearest competitors include the AMD Radeon Pro WX 5100 (8,863, only 0.1% ahead) and the AMD Radeon 550X (8,918, 0.8% ahead), both of which are very close to its score. The GTX 675MX sits near the AMD Radeon 880M (8,436, 0.1% behind) and the NVIDIA GeForce MX330 (8,458, 0.4% behind), with slightly more spread in its immediate neighborhood.

For compute workloads measured by OpenCL, the GTX 675MX is the clear choice. Its 960 shading units and 80 texture mapping units provide substantially more parallel hardware than the R9 M265X's 640 shading units and 40 TMUs. The NVIDIA part also carries a 256-bit memory bus versus AMD's 128-bit bus, which directly impacts memory bandwidth and, consequently, compute-heavy tasks. If the workload is OpenCL-based, the data says NVIDIA wins decisively.

The AMD card's only apparent advantage is its percentile ranking, which is a statistical artifact of the broader GPU landscape rather than a performance edge. At 44th percentile, it sits just ahead of the GTX 675MX's 43rd percentile, but this does not translate into any benchmark victory in the head-to-head data.

Architecture Differences

The two GPUs come from different architectural generations and design philosophies. The AMD Radeon R9 M265X uses the Venus chip built on GCN 1.0 architecture, manufactured on TSMC's 28 nm process. It packs 1,500 million transistors into a 123 mm² die, yielding a transistor density of 12.2 million per square millimeter. The NVIDIA GeForce GTX 675MX uses the GK104 chip on Kepler architecture, also on TSMC's 28 nm process, but with 3,540 million transistors on a much larger 294 mm² die, giving a density of 12.0 million per square millimeter.

The die size difference is substantial: NVIDIA's chip is nearly 2.4 times larger in area and holds over twice as many transistors. Yet the transistor densities are almost identical, which reflects the similar manufacturing process. The architectural divergence matters more. GCN 1.0 was AMD's compute-oriented design, emphasizing raw throughput per shader. Kepler was NVIDIA's efficiency-focused architecture, featuring a different shader scheduling approach and a more balanced mix of compute and graphics resources.

Memory subsystems differ significantly. Both cards use 2 GB of GDDR5, but the R9 M265X runs its memory at 1000 MHz (4 Gbps effective) across a 128-bit bus, yielding 64.00 GB/s of bandwidth. The GTX 675MX runs at 900 MHz (3.6 Gbps effective) across a 256-bit bus, delivering 115.2 GB/s. The wider bus gives NVIDIA a 44% bandwidth advantage despite the lower clock speed. This explains part of the OpenCL performance gap, as many compute workloads are memory-bandwidth-sensitive.

The shading resources also differ markedly. NVIDIA provides 960 shading units, 80 TMUs, and 32 ROPs. AMD provides 640 shading units, 40 TMUs, and 16 ROPs. In every category, NVIDIA has double or near-double the hardware. The pixel rate is 13.08 GPixel/s for NVIDIA versus 10.00 GPixel/s for AMD. The texture rate is 52.32 GTexel/s versus 25.00 GTexel/s. FP32 throughput is 1,255.7 GFLOPS versus 800.0 GFLOPS. NVIDIA leads in every measured throughput metric.

API support shows a reversal. The AMD card supports DirectX 12 (11_1), OpenGL 4.6, and Vulkan 1.2.170. The NVIDIA card supports DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175. The AMD part has a slightly higher DirectX feature level, while NVIDIA's Vulkan version is fractionally newer. Both are end-of-life products, with AMD's successor listed as Polaris Mobile and NVIDIA's as GeForce 700M.

Head-to-Head Benchmarks

The only direct comparison in the dataset is the Geekbench OpenCL test. The GTX 675MX scores 10,723, and the R9 M265X scores 8,851. The delta is -17.5% from AMD's perspective, meaning the AMD card trails by nearly a fifth. This is a substantial margin for a single benchmark, and it aligns with the hardware resource differences.

To put this in context, look at the rival sets. The R9 M265X's nearest rival, the AMD Radeon Pro WX 5100, scores 8,863, which is only 0.1% higher. The GTX 675MX's nearest rival, the AMD Radeon 880M, scores 8,436, which is 0.1% lower. The NVIDIA card outperforms its nearest rival by a smaller margin than the AMD card trails its nearest rival. This suggests the GTX 675MX is not just ahead of the R9 M265X, but also sits in a slightly more crowded performance neighborhood where its lead is less pronounced relative to other GPUs.

The 17.5% gap translates into real-world implications for OpenCL compute tasks. A workload that takes 100 seconds on the AMD card would take roughly 82.5 seconds on the NVIDIA card. This is not a marginal difference; it is a clear tier separation. The GTX 675MX's additional memory bandwidth (115.2 GB/s versus 64.00 GB/s) and higher FP32 throughput (1,255.7 GFLOPS versus 800.0 GFLOPS) are the likely drivers.

There are no other head-to-head benchmarks in the dataset. No gaming tests, no synthetic graphics tests, no power efficiency comparisons. The analysis rests entirely on this single OpenCL result, alongside the architectural specifications. That limitation should be kept in mind: the data shows NVIDIA winning the one test available, but it does not prove superiority across all workloads.

FAQ

Q: Which GPU has the higher OpenCL benchmark score?

A: The NVIDIA GeForce GTX 675MX scores 10,723 in Geekbench OpenCL, while the AMD Radeon R9 M265X scores 8,851. NVIDIA leads by 17.5% in this test.

Q: How do their memory bandwidths compare?

A: The GTX 675MX has 115.2 GB/s of bandwidth from a 256-bit bus with 900 MHz memory. The R9 M265X has 64.00 GB/s from a 128-bit bus with 1000 MHz memory. NVIDIA's bandwidth is nearly double.

Q: What are the transistor counts for each chip?

A: The AMD Venus chip contains 1,500 million transistors on a 123 mm² die. The NVIDIA GK104 chip contains 3,540 million transistors on a 294 mm² die. NVIDIA's chip has over twice the transistor count and more than double the die area.

Q: Do both GPUs support the same DirectX version?

A: No. The R9 M265X supports DirectX 12 (11_1), while the GTX 675MX supports DirectX 12 (11_0). AMD's implementation has a higher feature level.

Q: What is the percentile ranking for each GPU?

A: The R9 M265X ranks at the 44th percentile of all GPUs, while the GTX 675MX ranks at the 43rd percentile. Despite winning the head-to-head benchmark, NVIDIA sits one percentile lower in the overall distribution.

Q: Which GPU has more shading units?

A: The GTX 675MX has 960 shading units, compared to 640 for the R9 M265X. NVIDIA also has 80 TMUs versus 40, and 32 ROPs versus 16.

Specification Differences

| Specification | AMD Radeon R9 M265X | NVIDIA GeForce GTX 675MX |

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

| Chip | Venus | GK104 |

| Architecture | GCN 1.0 | Kepler |

| Transistors | 1,500 million | 3,540 million |

| Die Size | 123 mm² | 294 mm² |

| Transistor Density | 12.2M / mm² | 12.0M / mm² |

| Memory Clock | 1000 MHz (4 Gbps effective) | 900 MHz (3.6 Gbps effective) |

| Memory Bus Width | 128 bit | 256 bit |

| Memory Bandwidth | 64.00 GB/s | 115.2 GB/s |

| Shading Units | 640 | 960 |

| TMUs | 40 | 80 |

| ROPs | 16 | 32 |

| Pixel Rate | 10.00 GPixel/s | 13.08 GPixel/s |

| Texture Rate | 25.00 GTexel/s | 52.32 GTexel/s |

| FP32 | 800.0 GFLOPS | 1,255.7 GFLOPS |

| TDP | Not specified | 100 W |

| Slot Width | Not specified | MXM Module |

| Power Connectors | Not specified | None |

| Bus Interface | PCIe 3.0 x16 | MXM-B (3.0) |

| Display Outputs | Not specified | Portable Device Dependent |

| DirectX | 12 (11_1) | 12 (11_0) |

| Vulkan | 1.2.170 | 1.2.175 |

| Release Date | 2014-03-20 | 2012-09-30 |

| Predecessor | Solar System | GeForce 500M |

| Successor | Polaris Mobile | GeForce 700M |

| Generation | Gem System (R9 M200) | GeForce 600M |

The Verdict

The data points in one direction: the NVIDIA GeForce GTX 675MX is the faster GPU for OpenCL compute workloads. Its 10,723 score versus 8,851 represents a 17.5% advantage, and that lead is backed by substantial hardware superiority. NVIDIA's chip has 50% more shading units, double the TMUs, double the ROPs, and nearly double the memory bandwidth. The FP32 throughput is 57% higher. Across every measurable compute specification, the GTX 675MX wins.

The AMD Radeon R9 M265X does have one statistical point in its favor: the 44th percentile ranking versus NVIDIA's 43rd. But this is a narrow, one-point difference in the overall GPU distribution, and it does not appear in any direct benchmark result. When the two are tested against each other, NVIDIA wins the only test available.

Who should pick the AMD card? Users who prioritize the slightly higher DirectX feature level (12 11_1 versus 12 11_0) or who need a PCIe 3.0 x16 bus interface rather than an MXM-B connection. The AMD card also launched later, in March 2014 versus September 2012, which may matter for system compatibility in certain laptops. Its smaller die (123 mm² versus 294 mm²) and lower transistor count suggest it is a more modest part, potentially suitable for thinner or lighter systems, though the TDP is not specified for the AMD card to confirm this.

Who should pick the NVIDIA card? Anyone running OpenCL-based applications. The GTX 675MX delivers a clear performance advantage in the one benchmark available, and its hardware specifications support that result across memory bandwidth, shading throughput, and texture processing. The 100 W TDP is specified for this card, and it requires no power connectors, which simplifies integration into MXM-based portable devices. Its Vulkan support is marginally newer (1.2.175 versus 1.2.170), which could benefit compute applications using that API.

The verdict is straightforward: for raw compute performance, the GTX 675MX is the stronger choice by a meaningful margin. The R9 M265X offers a slightly higher percentile ranking and a more recent release date, but neither translates into a benchmark win. The data shows one winner, and it is NVIDIA.