NVIDIA GeForce 825M vs NVIDIA GeForce GTX 650 Comparison

The NVIDIA GeForce GTX 650 and the NVIDIA GeForce 825M are both end-of-life mobile and desktop parts built on the same 28 nm TSMC process, but they target very different physical realities. The GTX 650 is a single-slot desktop card with its own 6-pin power connector, while the 825M is an IGP (integrated graphics processor) for laptops with no dedicated power connectors. The benchmark data shows a clear, though not overwhelming, performance hierarchy between them.

Head-to-Head Benchmarks

The only direct benchmark comparison available is the Geekbench OpenCL test. In this test, the GTX 650 scores 4545 points, while the 825M scores 3694 points. This gives the GTX 650 a 23% lead over the 825M in raw compute throughput. This is a substantial margin, indicating that the desktop card is noticeably more capable for general-purpose GPU compute workloads like OpenCL acceleration.

Looking at the broader average benchmark scores reinforces this gap. The GTX 650 has an average benchmark score of 3823, while the 825M sits lower at 3694. While the gap in the average score is smaller than in the single OpenCL test, it still favors the GTX 650. The data does not include any benchmark tests where the 825M wins; the head-to-head table shows the GTX 650 winning the one test they share, with the 825M recording zero wins.

The GTX 650's advantage is rooted in its specifications. It has a memory bandwidth of 80.00 GB/s thanks to its 128-bit GDDR5 memory interface, compared to the 825M's much narrower 64-bit bus and slower DDR3 memory, which yields only 14.40 GB/s of bandwidth. This is a massive difference in memory throughput, which heavily influences performance in memory-bound tasks. The GTX 650 also has a higher pixel rate of 8.464 GPixel/s versus 7.528 GPixel/s for the 825M, and a higher texture rate of 33.86 GTexel/s versus 30.11 GTexel/s. The GTX 650's FP32 compute is also higher at 812.5 GFLOPS compared to 722.7 GFLOPS for the 825M.

Interestingly, both GPUs feature the same number of shading units (384) and texture mapping units (32). The core architectural difference is in the ROPs (render output units); the GTX 650 has 16 ROPs, while the 825M has only 8. This halved ROP count, combined with the drastically lower memory bandwidth, explains why the 825M trails in the fill-rate and bandwidth-dependent benchmarks.

Where Each One Wins

Based strictly on the data, the GTX 650 is the clear winner for any workload that benefits from higher memory bandwidth and fill rates. The 23% lead in OpenCL performance suggests it is the better choice for compute tasks, such as video encoding or GPU-accelerated applications. Its higher pixel rate and texture rate also indicate it would handle higher resolution textures and more complex geometry more effectively. The GTX 650's 80.00 GB/s of memory bandwidth is a significant advantage over the 825M's 14.40 GB/s, making it far more capable for any task that streams large amounts of data, such as texture-heavy gaming or high-resolution image processing.

The 825M's primary advantage is its physical form factor and power characteristics. It is an IGP, meaning it's designed to be soldered onto a laptop motherboard. It has a TDP of just 33 W and requires no power connectors, whereas the GTX 650 has a TDP of 65 W and requires a 1x 6-pin power connector and a 250 W suggested PSU. This makes the 825M the only viable option for thin-and-light laptops where space and power are at a premium. It also has a boost clock of 941 MHz, compared to the GTX 650's unspecified base/boost clocks, but this does not translate into a performance win in the available data.

The GTX 650 also holds an edge in its bus interface, featuring a full PCIe 3.0 x16 connection, while the 825M is limited to PCIe 3.0 x8. This lower interface bandwidth could further bottleneck the 825M in data-transfer-heavy scenarios. For a user building a desktop, the GTX 650 is clearly superior. For someone who is strictly limited to a laptop's integrated graphics, the 825M is the only choice, but the performance data indicates it is significantly weaker.

The Verdict

The data is unequivocal: the NVIDIA GeForce GTX 650 is the more powerful GPU. It beats the 825M by 23% in the only shared benchmark and has superior specs across the board in memory bandwidth, pixel rate, texture rate, and FP32 performance. The GTX 650's average benchmark score of 3823 places it in the 22nd percentile of all GPUs, a position it shares with the 825M, which also sits in the 22nd percentile. However, this percentile ranking is averaged across many different tests, and the head-to-head comparison shows a clear winner.

The 825M is not a competitor to the GTX 650 in terms of performance. Its only purpose is to provide basic graphics capability in a low-power, integrated form factor. The data shows it has exactly half the ROPs of the GTX 650 (8 vs 16) and a fraction of the memory bandwidth. If you are choosing between these two for a system you are building, the GTX 650 is the only logical choice for any performance-oriented task. The 825M is for a user who has no choice but to use an integrated GPU in a portable device.

Given the GTX 650's superior performance in the head-to-head test, it is the recommended part for anyone who can accommodate its single-slot, 65 W desktop footprint. The 825M's performance is simply too constrained by its 64-bit memory bus and DDR3 memory to be recommended for anything beyond basic tasks. The data shows the 825M is best avoided for anything but the most basic computing needs.

FAQ

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

A: The NVIDIA GeForce GTX 650 is faster, scoring 4545 points compared to the GeForce 825M's 3694 points, a difference of 23%.

Q: Do both GPUs have the same number of shading units?

A: Yes, both the GTX 650 and the 825M are equipped with 384 shading units and 32 texture mapping units.

Q: What is the biggest specification difference between the two?

A: The memory subsystem is the most significant difference. The GTX 650 uses a 128-bit GDDR5 interface providing 80.00 GB/s of bandwidth, while the 825M uses a 64-bit DDR3 interface providing only 14.40 GB/s.

Q: Can the GeForce 825M be used in a desktop PC?

A: The data describes it as an "IGP" (integrated graphics processor) with "Portable Device Dependent" display outputs, indicating it is designed for laptops and not as a standalone desktop card.

Q: Which GPU has a higher pixel fill rate?

A: The GTX 650 has a higher pixel rate of 8.464 GPixel/s compared to the 825M's 7.528 GPixel/s, due to its 16 ROPs versus the 825M's 8 ROPs.

Q: What is the average benchmark score for each GPU?

A: The GTX 650 has an average benchmark score of 3823, while the 825M has an average score of 3694. Both GPUs fall in the 22nd percentile of all GPUs.

Architecture Differences

Both GPUs are built on NVIDIA's Kepler architecture, but they represent different revisions. The GTX 650 uses the GK106 chip and is classified as "Kepler," while the 825M uses the GK208 chip and is classified as "Kepler 2.0." The GTX 650 is part of the GeForce 600 generation, whereas the 825M is from the GeForce 800M generation.

The transistor counts and die sizes differ significantly. The GTX 650's GK106 chip contains 2,540 million transistors on a 221 mm² die, resulting in a transistor density of 11.5M / mm². In contrast, the 825M's GK208 chip is much smaller, with 1,020 million transistors on an 87 mm² die, giving it a slightly higher transistor density of 11.7M / mm². This indicates the 825M is a more cut-down and power-efficient version of the architecture.

The most critical architectural difference is in the render output units. The GTX 650 has 16 ROPs, while the 825M has only 8. This means the 825M has half the pixel processing capability of the GTX 650. This difference, combined with the memory bus width, is the primary driver of the performance gap. Both support the same API levels, including DirectX 12 (11_0), OpenGL 4.6, and Vulkan 1.2.175.

Specification Differences

The following specifications differ between the two GPUs:

• Chip: The GTX 650 uses the GK106 chip, while the 825M uses the GK208 chip.
• Architecture: The GTX 650 is classified as Kepler, while the 825M is classified as Kepler 2.0.
• Generation: The GTX 650 is from GeForce 600, while the 825M is from GeForce 800M.
• Transistors: The GTX 650 has 2,540 million transistors, while the 825M has 1,020 million.
• Die Size: The GTX 650 has a 221 mm² die, while the 825M has an 87 mm² die.
• Transistor Density: The GTX 650 has a density of 11.5M / mm², while the 825M has 11.7M / mm².
• Boost Clock: The 825M has a boost clock of 941 MHz, while the GTX 650's boost clock is not specified.
• Memory Clock: The GTX 650 has a memory clock of 1250 MHz (5 Gbps effective), while the 825M has 900 MHz (1800 Mbps effective).
• Memory Type: The GTX 650 uses GDDR5, while the 825M uses DDR3.
• Memory Bus Width: The GTX 650 has a 128-bit bus, while the 825M has a 64-bit bus.
• Memory Bandwidth: The GTX 650 has 80.00 GB/s of bandwidth, while the 825M has 14.40 GB/s.
• ROPs: The GTX 650 has 16 ROPs, while the 825M has 8.
• Pixel Rate: The GTX 650 has a pixel rate of 8.464 GPixel/s, while the 825M has 7.528 GPixel/s.
• Texture Rate: The GTX 650 has a texture rate of 33.86 GTexel/s, while the 825M has 30.11 GTexel/s.
• FP32 Performance: The GTX 650 has 812.5 GFLOPS of FP32 compute, while the 825M has 722.7 GFLOPS.
• TDP: The GTX 650 has a TDP of 65 W, while the 825M has a TDP of 33 W.
• Slot Width: The GTX 650 is Single-slot, while the 825M is an IGP.
• Power Connectors: The GTX 650 requires 1x 6-pin, while the 825M requires None.
• Suggested PSU: The GTX 650 suggests a 250 W PSU, while the 825M has no suggested PSU.
• Bus Interface: The GTX 650 uses PCIe 3.0 x16, while the 825M uses PCIe 3.0 x8.
• Display Outputs: The GTX 650 has 1x DVI and 2x DisplayPort 1.2, while the 825M's outputs are Portable Device Dependent.
• Dimensions: The GTX 650 has a length of 147 mm (5.8 inches), while the 825M's dimensions are not listed.
• Release Date: The GTX 650 was released on 2013-11-26, while the 825M was released on 2014-01-26.
• Predecessor: The GTX 650's predecessor is GeForce 500, while the 825M's is GeForce 700M.
• Successor: The GTX 650's successor is GeForce 700, while the 825M's is GeForce 900M.