AMD Radeon R7 M265 vs NVIDIA GeForce GT 645M Comparison

Head-to-Head Benchmarks

The only directly comparable benchmark in the database is Geekbench OpenCL, and the result is decisively one-sided. The AMD Radeon R7 M265 scores 4929, while the NVIDIA GeForce GT 645M scores 2680. That is an 83.9% advantage for the AMD part, a massive gap that places these two mobile graphics solutions in entirely different performance tiers despite their similar specifications.

Context from the database makes this margin even more striking. The R7 M265's OpenCL score of 4929 puts it within 0.5% of the AMD FirePro W5130M (4904) and within 0.7% of the NVIDIA GeForce GTS 450 (4893). It effectively matches those desktop-class parts. The GT 645M's 2680, by contrast, sits far below its own nearest rivals in the aggregate standings. Its average benchmark score across all recorded tests is 4411, but that figure is propped up by its Geekbench Metal score of 5679 and Vulkan score of 4875, both of which are absent from the AMD card's data.

The GT 645M does have a narrower claim to relevance. Its Vulkan score of 4875 is nearly identical to the R7 M265's OpenCL result, and its Metal score of 5679 exceeds it. However, the direct head-to-head comparison uses the same API for both cards, and there the AMD part wins outright. The database records one win for the R7 M265 and zero for the GT 645M in their shared benchmark suite. That is the complete head-to-head picture: one test, one winner, and a decisive margin.

FAQ

Q: Which GPU is faster in the Geekbench OpenCL benchmark?

A: The AMD Radeon R7 M265 scores 4929, which is 83.9% higher than the NVIDIA GeForce GT 645M's 2680 in the same test.

Q: How do these GPUs compare to their nearest rivals in the database?

A: The R7 M265's average score of 4929 places it within 0% of the AMD Radeon R7 M360 (4931) and 0.7% of the NVIDIA GeForce GTS 450 (4893). The GT 645M's average of 4411 sits 0.5% above the NVIDIA GeForce 930M (4388) and 1.9% below the AMD Radeon R7 M260 (4499).

Q: What API support does each GPU offer?

A: The R7 M265 supports DirectX 12 (11_1), OpenGL 4.6, and Vulkan 1.2.170. The GT 645M supports DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175.

Q: Which GPU has a higher pixel fill rate?

A: The AMD Radeon R7 M265 achieves 6.600 GPixel/s, slightly ahead of the NVIDIA GeForce GT 645M's 6.240 GPixel/s.

Q: Which GPU has a higher texture fill rate?

A: The NVIDIA GeForce GT 645M achieves 24.96 GTexel/s, which is 26% higher than the AMD Radeon R7 M265's 19.80 GTexel/s.

Q: What is the memory configuration of both GPUs?

A: Both use 2 GB of DDR3 memory on a 128-bit bus, yielding identical 28.80 GB/s bandwidth. Both run at 900 MHz with 1800 Mbps effective speed.

Architecture Differences

The two GPUs come from rival architectures with fundamentally different design priorities. The AMD Radeon R7 M265 is built on GCN 1.0 using the Opal chip, while the NVIDIA GeForce GT 645M uses the Kepler architecture with the GK107 chip. Both are manufactured on TSMC's 28 nm process, but their transistor budgets and die sizes diverge significantly.

The NVIDIA chip packs 1,270 million transistors into a 118 mm² die, giving it a transistor density of 10.8 million per mm². The AMD chip uses 950 million transistors on a much smaller 77 mm² die, achieving a higher density of 12.3 million per mm². This means the AMD implementation crams more transistors into less silicon, a notable efficiency advantage at the same process node.

The functional unit counts tell a more nuanced story. Both GPUs have 384 shading units, so their raw shader throughput is comparable. However, the NVIDIA part doubles the AMD part in texture mapping units (32 versus 24) and render output units (16 versus 8). These extra units explain why the GT 645M achieves a higher texture rate of 24.96 GTexel/s against the R7 M265's 19.80 GTexel/s, and why its pixel rate of 6.240 GPixel/s trails only slightly despite the AMD card's higher clock speeds.

Clock behavior differs as well. The AMD R7 M265 runs at a base of 725 MHz with a boost of 825 MHz. The NVIDIA GT 645M runs at a lower base of 709 MHz and boosts to 780 MHz. The AMD card's higher clocks help it reach 633.6 GFLOPS of FP32 throughput, while the NVIDIA card manages 599.0 GFLOPS.

API support shows a small generational difference. AMD lists DirectX 12 (11_1) while NVIDIA lists DirectX 12 (11_0), a minor feature-level gap. Both support OpenGL 4.6, but NVIDIA's Vulkan driver is slightly newer at 1.2.175 versus AMD's 1.2.170.

The bus interface also differs: the AMD card uses PCIe 3.0 x8, while the NVIDIA card uses the full PCIe 3.0 x16 interface. For mobile parts with 2 GB of DDR3 memory, this bandwidth difference is unlikely to be the deciding factor in performance.

Specification Differences

The two GPUs differ across several recorded specifications. The AMD Radeon R7 M265 has a base clock of 725 MHz and a boost clock of 825 MHz, while the NVIDIA GeForce GT 645M runs at 709 MHz base and 780 MHz boost. The AMD card's higher clocks contribute to its FP32 throughput of 633.6 GFLOPS versus the NVIDIA card's 599.0 GFLOPS.

Texture and pixel processing favor opposite sides. The NVIDIA GT 645M has 32 texture mapping units and 16 render output units, against the AMD R7 M265's 24 TMUs and 8 ROPs. This yields a texture rate of 24.96 GTexel/s for NVIDIA versus 19.80 GTexel/s for AMD, and a pixel rate of 6.240 GPixel/s for NVIDIA versus 6.600 GPixel/s for AMD.

The silicon itself differs substantially. NVIDIA's GK107 chip measures 118 mm² with 1,270 million transistors, while AMD's Opal chip is 77 mm² with 950 million transistors. Transistor density reads 10.8 million per mm² for NVIDIA and 12.3 million per mm² for AMD.

Power characteristics are only recorded for the NVIDIA part, which lists a TDP of 32 W, a slot width of IGP, and no power connectors. The AMD card has no TDP or slot width data in the database.

The NVIDIA GT 645M uses PCIe 3.0 x16, while the AMD R7 M265 uses PCIe 3.0 x8. Display outputs for the NVIDIA card are listed as "Portable Device Dependent," and no display output data exists for the AMD card.

Release dates differ by over a year. The GT 645M launched on 2012-09-30, while the R7 M265 launched on 2014-01-08. NVIDIA's predecessor was GeForce 500M and its successor was GeForce 700M; AMD's predecessor was Solar System and its successor was Polaris Mobile. Both are marked as end-of-life production status.

Where Each One Wins

The AMD Radeon R7 M265 wins decisively in compute-oriented workloads as measured by Geekbench OpenCL. Its 4929 score versus the GT 645M's 2680 represents an 83.9% advantage, and this is the only benchmark where both cards have directly comparable results. The R7 M265 also holds the edge in pixel fill rate at 6.600 GPixel/s versus 6.240 GPixel/s, and in raw FP32 throughput at 633.6 GFLOPS versus 599.0 GFLOPS. Its higher boost clock of 825 MHz versus 780 MHz supports these wins.

The NVIDIA GeForce GT 645M wins in texture-heavy workloads. Its 32 TMUs against 24 give it a texture rate of 24.96 GTexel/s, a 26% advantage over the R7 M265's 19.80 GTexel/s. The NVIDIA card also doubles the ROP count (16 versus 8), which can benefit certain rasterization patterns even though its overall pixel rate is slightly lower. Its Vulkan score of 4875 and Metal score of 5679 from separate benchmark runs indicate that under different API paths, the NVIDIA card can produce higher absolute numbers than the AMD card's OpenCL result.

The GT 645M also holds advantages in memory bandwidth parity (identical 28.80 GB/s), a wider PCIe interface (x16 versus x8), and a lower recorded TDP of 32 W. For systems where power draw is a constraint, the NVIDIA part has documented efficiency data that the AMD part lacks.

The Verdict

The benchmark data points to a clear winner for general compute performance: the AMD Radeon R7 M265. Its Geekbench OpenCL score of 4929 versus 2680 is not a marginal lead but a dominant one, placing it 83.9% ahead of the GT 645M in their only shared test. The AMD card also leads in FP32 throughput and pixel rate, and its smaller die with higher transistor density suggests a more efficient silicon design.

The NVIDIA GeForce GT 645M has legitimate strengths for specific use cases. Its texture rate of 24.96 GTexel/s is substantially higher, which matters for games and applications that stress texture sampling. Its Vulkan and Metal scores from separate runs indicate strong performance under those APIs, and its documented 32 W TDP gives system designers a concrete power figure to plan around.

For users choosing between these two end-of-life mobile GPUs, the decision hinges on workload. If the primary tasks involve OpenCL compute, general shader work, or applications that favor higher clocks and FP32 throughput, the R7 M265 is the superior option by a wide margin. If texture-heavy rendering or API-specific workloads (Vulkan, Metal) dominate, the GT 645M's architecture offers compensating advantages, though its DirectX 12 feature level is slightly lower at 11_0 versus 11_1.

The database records one head-to-head win for the R7 M265 and none for the GT 645M. The verdict follows that data: the AMD Radeon R7 M265 is the stronger all-around performer in direct comparison, while the NVIDIA GeForce GT 645M remains a viable alternative only for texture-bound tasks or systems where its lower TDP and wider bus interface are decisive factors.