AMD Radeon RX 560 vs NVIDIA GeForce GT 645M Comparison

# Head-to-Head Benchmarks

The AMD Radeon RX 560 utterly dominates the NVIDIA GeForce GT 645M in every measurable benchmark. The data shows a complete sweep: 2 wins for the RX 560, 0 for the GT 645M. There is no statistical ambiguity here — the margin is enormous in both tests.

The Geekbench Metal test delivers the smaller of the two gaps but still a decisive one. The RX 560 scores 18,941 points against the GT 645M's 5,679. That is a 233.5% advantage — meaning the AMD part delivers more than three times the Metal performance of the older NVIDIA chip. For any application leveraging Apple's Metal API, this is a generational chasm, not a competitive race.

The Geekbench OpenCL result is even more lopsided. The RX 560 posts 16,472 points while the GT 645M manages only 2,680. That translates to a 514.6% delta — the AMD card outperforms the NVIDIA part by a factor of roughly six. OpenCL workloads, whether compute tasks or GPU-accelerated rendering, will see the RX 560 as the only viable option between these two.

It is importantly the GT 645M has no DirectX 10, 11, 12, or 9 benchmark scores in the data, nor any Passmark results. The RX 560, by contrast, has a full suite: Passmark DirectX 10 at 16, DirectX 11 at 25, DirectX 12 at 21, DirectX 9 at 57, G2D at 485, G3D at 3671, and GPU compute at 1437. The absence of comparable data for the GT 645M means the head-to-head comparison is limited to those two Geekbench tests, but the pattern is unambiguous — wherever both are measured, the RX 560 wins by a landslide.

Architecture Differences

The architectural gap between these two GPUs is generational and foundational. The RX 560 is built on AMD's GCN 4.0 architecture, using the Polaris 21 chip, while the GT 645M relies on NVIDIA's Kepler architecture with the GK107 chip. These are from different eras of GPU design, and the process node difference alone tells that story.

The RX 560 is fabricated on a 14 nm process at GlobalFoundries, while the GT 645M uses a 28 nm process at TSMC. The smaller node allows the AMD chip to pack 3,000 million transistors into a 123 mm² die, yielding a transistor density of 24.4 million per square millimeter. The GT 645M, by contrast, houses 1,270 million transistors on a 118 mm² die — a density of just 10.8 million per square millimeter. The RX 560 fits more than twice the transistor count into a nearly identical footprint.

Core configuration separates them further. The RX 560 fields 1,024 shading units, 64 texture mapping units, and 16 ROPs. The GT 645M has 384 shading units, 32 TMUs, and 16 ROPs. That is roughly 2.7 times the shading units and double the texture units on the AMD side, with ROP count matching at 16.

Clock speeds amplify the core-count advantage. The RX 560 runs at a 1175 MHz base and 1275 MHz boost, while the GT 645M sits at 709 MHz base and 780 MHz boost. The AMD card's higher clock speeds, combined with its larger core configuration, produce a pixel rate of 20.40 GPixel/s and a texture rate of 81.60 GTexel/s. The GT 645M manages 6.240 GPixel/s and 24.96 GTexel/s. FP32 compute tells a similar story: 2.611 TFLOPS for the RX 560 versus 599.0 GFLOPS for the GT 645M. The AMD card also supports FP16 at 2.611 TFLOPS (1:1), a feature entirely absent from the NVIDIA chip's specification sheet.

Memory architecture adds another layer of separation. The RX 560 comes with 4 GB of GDDR5 on a 128-bit bus, delivering 112.0 GB/s of bandwidth at a 1750 MHz memory clock (7 Gbps effective). The GT 645M offers only 2 GB of DDR3 on the same 128-bit bus, with bandwidth of just 28.80 GB/s at 900 MHz (1800 Mbps effective). The RX 560 has nearly four times the memory bandwidth — a critical factor for texture-heavy workloads and higher resolutions.

API support also diverges. The RX 560 supports DirectX 12 (12_0), OpenGL 4.6, and Vulkan 1.3. The GT 645M lists DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175. The feature-level difference in DirectX 12 means the AMD card can access more modern rendering features. The RX 560 also has a PCIe 3.0 x8 interface versus the GT 645M's PCIe 3.0 x16, though the bandwidth difference is unlikely to matter given the RX 560's overwhelming performance lead elsewhere.

Where Each One Wins

The RX 560 wins everywhere the data allows a comparison. In Geekbench Metal, it leads by 233.5%. In Geekbench OpenCL, it leads by 514.6%. These are the only two head-to-head results available, and the AMD card takes both without challenge.

For gaming and 3D rendering, the RX 560 is the clear choice. Its Passmark G3D score of 3671, DirectX 11 score of 25, and DirectX 12 score of 21 indicate a part capable of handling modern game titles at playable settings, particularly at 1080p. The GT 645M has no comparable DirectX or Passmark scores in the data, which suggests its legacy Kepler architecture was not even tested under those workloads — a telling omission.

Compute workloads favor the RX 560 overwhelmingly. Its Geekbench OpenCL score of 16,472 versus 2,680 for the GT 645M means any GPU-accelerated compute task — video encoding, machine learning inference, scientific simulation — will run dramatically faster on the AMD part. The Passmark GPU compute score of 1437 for the RX 560 reinforces this, while the GT 645M again has no data point.

The GT 645M's only potential advantages are qualitative. It consumes 32 W TDP against the RX 560's 75 W, making it a more power-efficient part in absolute terms. It is also an IGP (integrated graphics processor) form factor, meaning it requires no expansion slot and can be embedded in a portable device. The RX 560 is a dual-slot card measuring 170 mm (6.7 inches) in length with no power connectors and a suggested PSU of 250 W. For a desktop build with a standard power supply, the RX 560's power draw is trivial. For a thin-and-light laptop from 2012, the GT 645M's integrated nature was its raison d'être.

One more data point favors the RX 560 in terms of ecosystem maturity: the AMD card has a launch MSRP of 99 USD. The GT 645M has no listed launch MSRP. That said, both parts are end-of-life, so launch pricing is historical context rather than a purchasing guide.

The Verdict

The data compels a singular verdict: choose the AMD Radeon RX 560 over the NVIDIA GeForce GT 645M in virtually every scenario. The performance delta is not marginal — it is anywhere from 2.3x to 6.1x depending on the workload. The RX 560 wins both head-to-head benchmarks, holds a 26th percentile ranking among all GPUs (matching the GT 645M's percentile, but with far higher absolute scores), and offers a more modern feature set across the board.

The GT 645M's only defensible use case is a legacy system where the integrated form factor is mandatory and power draw is the primary constraint. At 32 W versus 75 W, it draws less than half the power. But that advantage comes with a 514.6% compute deficit and a 233.5% Metal deficit. If you are running anything beyond basic 2D desktop tasks, the RX 560 is the only rational choice.

The RX 560's 4 GB of GDDR5 memory versus 2 GB of DDR3 is not just a capacity difference — the bandwidth gap (112.0 GB/s versus 28.80 GB/s) means the AMD card can feed its far larger shader array without stalling. The 14 nm process node, GCN 4.0 architecture, and support for Vulkan 1.3 and DirectX 12 (12_0) ensure the RX 560 remains relevant for modern software, while the GT 645M's Kepler architecture is firmly a product of its 2012 era.

For anyone assembling a budget desktop build or upgrading an older system, the RX 560 is the data-backed pick. For anyone maintaining a vintage laptop with a soldered GT 645M, the data offers no upgrade path — but it does confirm that the old NVIDIA part is strictly outclassed by even a modest modern discrete GPU.

FAQ

Q: Which GPU wins in Geekbench Metal performance?

A: The AMD Radeon RX 560 wins decisively with a score of 18,941 against the NVIDIA GeForce GT 645M's 5,679, a 233.5% advantage.

Q: What is the biggest performance gap between the two cards?

A: The Geekbench OpenCL test shows the largest delta: the RX 560 scores 16,472 while the GT 645M scores 2,680, giving the AMD card a 514.6% lead.

Q: How do their memory bandwidths compare?

A: The RX 560 offers 112.0 GB/s of bandwidth from 4 GB of GDDR5 on a 128-bit bus, while the GT 645M provides 28.80 GB/s from 2 GB of DDR3 on the same 128-bit bus.

Q: Which GPU has more shading units?

A: The RX 560 has 1,024 shading units, while the GT 645M has 384 — the AMD part has roughly 2.7 times the shader count.

Q: Do both GPUs support the same DirectX version?

A: No. The RX 560 supports DirectX 12 (12_0), while the GT 645M supports DirectX 12 (11_0), meaning the AMD card has a higher feature level.

Q: What is the thermal design power of each card?

A: The RX 560 has a TDP of 75 W, while the GT 645M has a TDP of 32 W.

Specification Differences

| Specification | AMD Radeon RX 560 | NVIDIA GeForce GT 645M |

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

| Architecture | GCN 4.0 | Kepler |

| Chip | Polaris 21 | GK107 |

| Process Node | 14 nm | 28 nm |

| Foundry | GlobalFoundries | TSMC |

| Transistors | 3,000 million | 1,270 million |

| Die Size | 123 mm² | 118 mm² |

| Transistor Density | 24.4M / mm² | 10.8M / mm² |

| Base Clock | 1175 MHz | 709 MHz |

| Boost Clock | 1275 MHz | 780 MHz |

| Memory Clock | 1750 MHz (7 Gbps effective) | 900 MHz (1800 Mbps effective) |

| Memory Size | 4 GB | 2 GB |

| Memory Type | GDDR5 | DDR3 |

| Memory Bus Width | 128 bit | 128 bit |

| Memory Bandwidth | 112.0 GB/s | 28.80 GB/s |

| Shading Units | 1024 | 384 |

| TMUs | 64 | 32 |

| ROPs | 16 | 16 |

| Pixel Rate | 20.40 GPixel/s | 6.240 GPixel/s |

| Texture Rate | 81.60 GTexel/s | 24.96 GTexel/s |

| FP32 Performance | 2.611 TFLOPS | 599.0 GFLOPS |

| FP16 Performance | 2.611 TFLOPS (1:1) | — |

| TDP | 75 W | 32 W |

| Slot Width | Dual-slot | IGP |

| Power Connectors | None | None |

| Suggested PSU | 250 W | — |

| Bus Interface | PCIe 3.0 x8 | PCIe 3.0 x16 |

| Display Outputs | 1x DVI, 1x HDMI 2.0b, 1x DisplayPort 1.4a | Portable Device Dependent |

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

| OpenGL | 4.6 | 4.6 |

| Vulkan | 1.3 | 1.2.175 |

| Release Date | 2017-04-17 | 2012-09-30 |

| Production Status | End-of-life | End-of-life |

| Predecessor | Arctic Islands | GeForce 500M |

| Successor | Vega | GeForce 700M |

| Launch MSRP | 99 USD | — |

| Avg Benchmark Score | 4569 | 4411 |