AMD Radeon R5 Graphics vs NVIDIA GeForce GT 645M Comparison

Head-to-Head Benchmarks

The recorded data presents a clear split between these two mobile graphics solutions. Across the two shared workload tests, each adapter claims one decisive victory, and the margins are substantial in both directions.

In Geekbench OpenCL, the AMD Radeon R5 Graphics posts a score of 5183, while the NVIDIA GeForce GT 645M manages 2680. The delta is 48.3% in favor of AMD. This is not a marginal difference; it is a dominant performance gap in compute-oriented workloads that leverage OpenCL. The AMD part more than doubles the NVIDIA score in this specific test.

The situation reverses completely in Geekbench Vulkan. Here, the NVIDIA GeForce GT 645M scores 4875, against 2582 for the AMD Radeon R5 Graphics. The delta is 88.8% in favor of NVIDIA. The NVIDIA adapter nearly doubles the AMD score in Vulkan. That is a massive swing, and it suggests that the two architectures respond very differently to the API and workload characteristics.

Looking at the overall averages, the NVIDIA GeForce GT 645M has an average benchmark score of 4411 across its tested workloads. The AMD Radeon R5 Graphics has an average of 3883. That places the NVIDIA part roughly 13.6% higher in aggregate, but the caveat is that the averages are computed over different test suites. The NVIDIA part was measured in Geekbench Metal, OpenCL, and Vulkan. The AMD part was measured only in OpenCL and Vulkan. The absence of a Metal score for AMD complicates a direct comparison, but within the shared tests, the split is exactly one win apiece.

Where Each One Wins

The data supports a clear use-case division. If the workload is built on OpenCL, the AMD Radeon R5 Graphics is the stronger candidate. Its 5183 OpenCL score is far ahead of the NVIDIA part's 2680. This suggests that applications, filters, or compute tasks that rely on OpenCL acceleration will see significantly better throughput on the AMD solution. The 48.3% delta is large enough to be a deciding factor for any user whose primary tasks are OpenCL-based.

Conversely, if the workload is built on Vulkan, the NVIDIA GeForce GT 645M is the definitive winner. Its 4875 Vulkan score versus 2582 for AMD represents an 88.8% advantage. This is the single largest performance gap in the entire comparison. For gaming or applications that leverage Vulkan, the NVIDIA part is clearly the better choice. The margin is so wide that it dominates any other consideration between these two.

For Metal-based workloads, only the NVIDIA GeForce GT 645M has a recorded score. Its Geekbench Metal result is 5679. The AMD Radeon R5 Graphics has no recorded Metal score in the database. This absence is notable for users in Apple ecosystems, where Metal is the primary graphics API, but the data simply does not provide a comparable AMD number. What the data does show is that the NVIDIA part's Metal score is its highest of the three tests, exceeding its Vulkan score of 4875 and its OpenCL score of 2680 by a wide margin.

Architecture Differences

The underlying hardware designs explain the benchmark behavior. The NVIDIA GeForce GT 645M is built on the Kepler architecture, using the GK107 chip, fabricated on a 28 nm process at TSMC. The chip contains 1,270 million transistors on a die size of 118 mm², giving a transistor density of 10.8M per mm². The AMD Radeon R5 Graphics uses the GCN 2.0 architecture, with the Spectre SL chip, also on a 28 nm process but fabricated at GlobalFoundries. That chip contains 2,410 million transistors on a die size of 245 mm², giving a density of 9.8M per mm². The AMD chip is physically larger and has nearly twice the transistor count.

The compute resources differ significantly. NVIDIA's GT 645M has 384 shading units, 32 texture mapping units, and 16 ROPs. AMD's R5 Graphics has 256 shading units, 16 TMUs, and only 4 ROPs. The NVIDIA part has more of each resource type. This is reflected in the theoretical pixel and texture rates. NVIDIA's pixel rate is 6.240 GPixel/s versus 3.032 GPixel/s for AMD. NVIDIA's texture rate is 24.96 GTexel/s versus 12.13 GTexel/s for AMD. NVIDIA's FP32 throughput is 599.0 GFLOPS versus 388.1 GFLOPS for AMD. On paper, NVIDIA has a clear raw throughput advantage.

The memory configurations are a major differentiator. The NVIDIA GT 645M has dedicated 2 GB of DDR3 memory on a 128 bit bus, providing 28.80 GB/s of bandwidth. The memory clock is 900 MHz, with 1800 Mbps effective. The AMD R5 Graphics uses system shared memory, with the type, bus width, and bandwidth all listed as system dependent. This means the AMD part's memory performance is entirely dependent on the host system's RAM configuration, which can vary widely. The NVIDIA part's dedicated memory provides a fixed and predictable bandwidth.

Power characteristics also differ. The NVIDIA GT 645M has a TDP of 32 W, while the AMD R5 Graphics has a TDP of 15 W. Both are integrated graphics solutions with an IGP slot width. The NVIDIA part uses a PCIe 3.0 x16 bus interface, while the AMD part is an IGP with no separate bus interface listed. The NVIDIA part has no power connectors, and its display outputs are portable device dependent. The AMD part's display outputs are motherboard dependent.

API support shows a notable difference. The AMD R5 Graphics supports DirectX 12 (12_0), while the NVIDIA GT 645M supports DirectX 12 (11_0). This means the AMD part supports the full DirectX 12 feature level, while the NVIDIA part is limited to the 11_0 feature level. Both support OpenGL 4.6. In Vulkan, the NVIDIA part supports version 1.2.175, while the AMD part supports version 1.2.170. The NVIDIA part has a slightly newer Vulkan version.

The release timeline shows a generational gap. The NVIDIA GT 645M was released in 2012, with the GeForce 600M generation, succeeding the GeForce 500M and preceding the GeForce 700M. The AMD R5 Graphics was released in 2014, as part of the GCN 2.0 IGP series based on Kaveri, succeeding TeraScale 3 IGP and preceding GCN 3.0 IGP. Both are end-of-life products.

FAQ

Q: Which GPU is faster in OpenCL?

A: The AMD Radeon R5 Graphics is significantly faster in OpenCL. It scores 5183 in Geekbench OpenCL, versus 2680 for the NVIDIA GeForce GT 645M. This is a 48.3% advantage for AMD.

Q: Which GPU is faster in Vulkan?

A: The NVIDIA GeForce GT 645M is dramatically faster in Vulkan. It scores 4875 in Geekbench Vulkan, versus 2582 for the AMD Radeon R5 Graphics. This is an 88.8% advantage for NVIDIA.

Q: How does the average benchmark score compare?

A: The NVIDIA GeForce GT 645M has an average benchmark score of 4411, while the AMD Radeon R5 Graphics has an average of 3883. The NVIDIA part is roughly 13.6% higher, but the scores are based on different test sets.

Q: What are the memory configurations?

A: The NVIDIA GeForce GT 645M has 2 GB of dedicated DDR3 memory on a 128 bit bus, with 28.80 GB/s bandwidth. The AMD Radeon R5 Graphics uses system shared memory, with bandwidth listed as system dependent.

Q: Which GPU has more shading units?

A: The NVIDIA GeForce GT 645M has 384 shading units, while the AMD Radeon R5 Graphics has 256 shading units. NVIDIA also has more TMUs (32 versus 16) and more ROPs (16 versus 4).

Q: What is the TDP of each GPU?

A: The NVIDIA GeForce GT 645M has a TDP of 32 W. The AMD Radeon R5 Graphics has a TDP of 15 W.

The Verdict

The performance data dictates a clear choice based on workload. For Vulkan-based applications, the NVIDIA GeForce GT 645M is the only sensible option. Its 88.8% lead over the AMD part in the Vulkan test is overwhelming. No other metric in the comparison comes close to this margin. If a user's primary software uses Vulkan, the NVIDIA part is categorically superior.

For OpenCL-based workloads, the AMD Radeon R5 Graphics is the stronger choice. Its 48.3% lead in the OpenCL test is substantial and consistent with its higher compute capabilities in that API. Users running OpenCL compute tasks should favor the AMD solution.

The raw specifications favor NVIDIA. The GT 645M has more shading units, TMUs, ROPs, higher pixel rate, higher texture rate, and higher FP32 throughput. It also has dedicated memory with fixed bandwidth, which is generally more reliable than system shared memory. The NVIDIA part supports a newer Vulkan version and has a higher average benchmark score. However, the AMD part's advantage in OpenCL and its lower TDP of 15 W versus 32 W are notable.

The API support difference is also relevant. The AMD R5 Graphics supports DirectX 12 (12_0), the full feature level, while the NVIDIA GT 645M supports only DirectX 12 (11_0). For DirectX 12 workloads that require the 12_0 feature level, the AMD part has an advantage that the benchmark scores do not directly capture.

The database percentiles place the NVIDIA GT 645M at the 26th percentile of all GPUs, and the AMD R5 Graphics at the 23rd percentile. Both are low-end parts, but the NVIDIA part is ranked slightly higher. The nearest rivals for the NVIDIA part include the NVIDIA GeForce 930M with an average score of 4388 and a delta of 0.5%, and the Intel Iris Pro Graphics 5200 with a score of 4360 and a delta of 1.2%. The nearest rivals for the AMD part include the NVIDIA Quadro 2000 with a score of 3898 and a delta of -0.4%, and the NVIDIA GeForce MX110 with a score of 3834 and a delta of 1.3%.

The final recommendation is workload-dependent. If the user's environment is Vulkan-centric, the NVIDIA GeForce GT 645M is the clear winner. If the environment is OpenCL-centric, the AMD Radeon R5 Graphics is the better choice. For general use with mixed workloads, the NVIDIA part has a higher average score, more raw throughput, and dedicated memory, which tips the balance in its favor, but the AMD part's lower power draw and full DirectX 12 feature support are meaningful counterpoints. The data does not support a universal winner, but it does provide a definitive answer for each specific API workload.