AMD Radeon R7 M260X vs NVIDIA GeForce GT 645M Comparison

Head-to-Head Benchmarks

The recorded data shows a fascinating split between these two mobile graphics processors. In the Geekbench OpenCL test, the AMD Radeon R7 M260X delivers a score of 5690, while the NVIDIA GeForce GT 645M trails significantly at 2680. This represents a massive 112.3% advantage for the AMD part, more than doubling the NVIDIA score in this compute-oriented workload. The OpenCL result is the clearest statement of raw throughput capability between the two, and it aligns with the theoretical peak numbers in the database: the AMD chip reaches 549.1 GFLOPS of FP32 performance, while the NVIDIA part is rated at 599.0 GFLOPS. Interestingly, the NVIDIA card actually has a higher theoretical FP32 figure, yet it loses decisively in the OpenCL benchmark, suggesting driver efficiency or architecture-specific scheduling plays a major role.

The Vulkan test tells a different story. Here, the NVIDIA GeForce GT 645M scores 4875, edging out the AMD Radeon R7 M260X which scores 4631. The delta is 5% in NVIDIA's favor, a modest but consistent margin. Vulkan is a lower-level API that exposes hardware capabilities more directly, and the Kepler architecture in the GT 645M appears to handle this workload with better efficiency. The database shows the NVIDIA card also has a Metal benchmark score of 5679, though no comparable Metal result exists for the AMD part, so a direct comparison in that API is not possible from the recorded data.

Looking at the average benchmark scores across all recorded tests, the AMD Radeon R7 M260X sits at 5161, while the NVIDIA GeForce GT 645M averages 4411. That is a 17% overall advantage for AMD when aggregating all available benchmarks. The AMD card also holds a higher percentile rank against all GPUs at 30, compared to NVIDIA's 26. However, the head-to-head wins are evenly split at one each, which indicates the two parts have distinct strengths rather than one being universally superior.

Where Each One Wins

The AMD Radeon R7 M260X wins decisively in OpenCL compute workloads. This makes it the better choice for applications that leverage general-purpose GPU computing through OpenCL, such as certain video encoding filters, physics simulations, or data-parallel tasks. The 112.3% margin over the GT 645M is not a marginal difference; it is a dominant performance gap that would be immediately noticeable in any OpenCL-heavy application. The AMD part's GCN 1.0 architecture, with its 384 shading units and 24 texture mapping units, appears to scale well with the compute-oriented nature of OpenCL.

The NVIDIA GeForce GT 645M wins in Vulkan graphics workloads. The 5% advantage in the Geekbench Vulkan test suggests better driver optimization or hardware scheduling for this modern graphics API. Vulkan is increasingly relevant for gaming and real-time graphics, so this win matters for anyone planning to use the GPU for DirectX 12 or Vulkan-based titles. The GT 645M also has a Metal benchmark score of 5679, which is higher than its OpenCL score, indicating strong performance in Apple's Metal API, though the AMD card has no recorded Metal score to compare against. For users on macOS or iOS development environments, the NVIDIA part may hold an edge, but the lack of comparative data prevents a definitive statement.

In terms of overall average benchmark score, the AMD Radeon R7 M260X is the aggregate winner. The database places it 0.1% above the NVIDIA Quadro K3100M and 1.9% above the AMD Radeon R7 240 among its nearest rivals. The NVIDIA GT 645M, by contrast, sits 0.5% above the GeForce 930M and 1.2% above the Intel Iris Pro Graphics 5200. These relative positions confirm that the AMD part occupies a slightly higher performance tier in the overall hierarchy.

Architecture Differences

The AMD Radeon R7 M260X uses the Opal chip built on GCN 1.0 architecture, manufactured on a 28 nm process at TSMC. The die contains 950 million transistors on a 77 mm² package, yielding a transistor density of 12.3 million per square millimeter. The GCN 1.0 design is compute-oriented, with a uniform shader array that handles both graphics and compute tasks. The AMD card features 384 shading units, 24 texture mapping units, and 8 raster operation units. Its pixel rate is 5.720 GPixel/s, and its texture rate is 17.16 GTexel/s.

The NVIDIA GeForce GT 645M uses the GK107 chip built on Kepler architecture, also on a 28 nm process at TSMC. The die is larger at 118 mm² and packs 1,270 million transistors, but the transistor density is lower at 10.8 million per square millimeter. Kepler was designed with a focus on power efficiency and geometry throughput. The NVIDIA card has 384 shading units, 32 texture mapping units, and 16 raster operation units. Its pixel rate is higher at 6.240 GPixel/s, and its texture rate is substantially higher at 24.96 GTexel/s.

The transistor count difference is notable: NVIDIA uses 33.7% more transistors (1,270 million versus 950 million) on a die that is 53.2% larger by area. Yet the AMD part achieves a higher transistor density, which reflects a more compact design. The shading unit count is identical at 384, but NVIDIA allocates more TMUs and ROPs, which explains its higher texture and pixel fill rates. These architectural choices suggest NVIDIA focused on rasterization throughput, while AMD concentrated on compute density and memory bandwidth efficiency.

Specification Differences

The most significant specification difference lies in memory configuration. The AMD Radeon R7 M260X uses 1024 MB of GDDR5 memory on a 128-bit bus, delivering 64.00 GB/s of bandwidth. The NVIDIA GeForce GT 645M uses 2 GB of DDR3 memory on the same 128-bit bus, but bandwidth drops to 28.80 GB/s. This is a 122% bandwidth advantage for AMD, which explains the OpenCL performance gap. However, NVIDIA's 2 GB capacity is double that of AMD, which matters for modern games and applications that require larger framebuffers.

Clock speeds also differ substantially. The AMD card runs at a base clock of 620 MHz with a boost of 715 MHz, while the NVIDIA card runs at 709 MHz base and 780 MHz boost. NVIDIA's clocks are higher, but the effective memory speed tells a different story: AMD's memory runs at 4 Gbps effective, while NVIDIA's runs at 1800 Mbps effective. This reinforces the bandwidth disparity.

The TDP is another differentiator. The NVIDIA GeForce GT 645M is rated at 32 W, while the AMD Radeon R7 M260X has no TDP listed in the database. NVIDIA's lower power draw, combined with its higher clock speeds, suggests better energy efficiency per clock cycle. The bus interface also differs: AMD uses PCIe 3.0 x8, while NVIDIA uses PCIe 3.0 x16, giving NVIDIA double the host interface bandwidth, though this matters less for mobile GPUs.

API support shows a split: AMD supports DirectX 12 (11_1), while NVIDIA supports DirectX 12 (11_0). Both support OpenGL 4.6, but NVIDIA's Vulkan version is newer at 1.2.175 versus AMD's 1.2.170. Release dates are far apart: the NVIDIA card launched on September 30, 2012, while the AMD card launched on December 5, 2015. The NVIDIA part's predecessor is GeForce 500M and successor is GeForce 700M; the AMD part's predecessor is Solar System and successor is Polaris Mobile.

FAQ

Q: Which GPU has higher memory bandwidth?

A: The AMD Radeon R7 M260X has 64.00 GB/s of bandwidth using GDDR5 memory, while the NVIDIA GeForce GT 645M has 28.80 GB/s using DDR3 memory. AMD's bandwidth is 122% higher.

Q: How do the two compare in Vulkan performance?

A: The NVIDIA GeForce GT 645M scores 4875 in Geekbench Vulkan, while the AMD Radeon R7 M260X scores 4631. NVIDIA wins by 5% in this test.

Q: Which GPU has more texture mapping units?

A: The NVIDIA GeForce GT 645M has 32 TMUs, while the AMD Radeon R7 M260X has 24. NVIDIA's texture rate is 24.96 GTexel/s versus 17.16 GTexel/s for AMD.

Q: What is the average benchmark score difference?

A: The AMD Radeon R7 M260X has an average benchmark score of 5161, while the NVIDIA GeForce GT 645M averages 4411. AMD leads by 17% in aggregate.

Q: Which GPU has a higher transistor count?

A: The NVIDIA GeForce GT 645M contains 1,270 million transistors on its GK107 chip, while the AMD Radeon R7 M260X contains 950 million on its Opal chip. NVIDIA uses 33.7% more transistors.

Q: Do both GPUs support DirectX 12?

A: Yes, both support DirectX 12, but AMD supports version 12 (11_1) while NVIDIA supports version 12 (11_0). The AMD implementation is slightly more advanced.

The Verdict

The data supports a clear split recommendation. For compute-heavy tasks that rely on OpenCL, the AMD Radeon R7 M260X is the unequivocal choice. Its 112.3% lead in the OpenCL benchmark, coupled with 122% higher memory bandwidth, makes it far superior for GPGPU workloads. The 64.00 GB/s of bandwidth from GDDR5 memory is a decisive advantage that no driver optimization can overcome on the NVIDIA side. Users running OpenCL-based video transcoding, scientific simulations, or data-parallel algorithms should select the AMD part without hesitation.

For Vulkan-based graphics workloads, the NVIDIA GeForce GT 645M takes the win. Its 5% margin in the Vulkan benchmark, combined with a recorded Metal score of 5679, indicates strong modern-API performance. The higher pixel rate of 6.240 GPixel/s and texture rate of 24.96 GTexel/s give it an edge in rasterization-heavy scenes, even though its bandwidth is much lower. Gamers or developers targeting Vulkan or Metal should prefer the NVIDIA card.

The overall average benchmark score favors AMD at 5161 versus 4411, and the AMD card holds a higher percentile at 30 versus 26. However, the win split is exactly even at one benchmark each. This suggests the choice depends entirely on the intended workload. The AMD card is a compute specialist with a bandwidth advantage; the NVIDIA card is a graphics specialist with better fill rates and lower power draw at 32 W. Users prioritizing memory capacity should note the NVIDIA card's 2 GB versus AMD's 1 GB, which matters for larger textures and higher resolutions. The database ultimately shows two differently optimized parts, and the correct pick follows the application, not the aggregate score.