NVIDIA GeForce GT 555M vs NVIDIA GeForce GTX 680M Comparison

# NVIDIA GeForce GTX 680M vs NVIDIA GeForce GT 555M

The NVIDIA GeForce GTX 680M and NVIDIA GeForce GT 555M represent two distinct eras of mobile graphics, separated by a full architecture generation and a significant performance gulf. The GTX 680M sits in the 39th percentile of all GPUs with an average benchmark score of 7023, while the GT 555M trails at the 37th percentile with an average score of 6493. The data shows a clear hierarchy, but the details of where and why the GTX 680M dominates reveal the deeper story.

Head-to-Head Benchmarks

The only directly comparable benchmark between the two GPUs is Geekbench OpenCL, and the result is decisive. The GTX 680M scores 9230, while the GT 555M manages 6493. That translates to a 42.2% advantage for the GTX 680M, a margin that dwarfs the differences seen in their respective nearest-rival comparisons.

To put that 42.2% gap in context, look at how each card sits among its own peers. The GTX 680M's nearest rival, the NVIDIA T600, scores 7035 on average, which is a negligible 0.2% ahead of the GTX 680M. The AMD Radeon R5 M240 is 0.7% behind at 6975, and the NVIDIA GeForce GTX 675M trails by 1.1% at 6946. The GTX 680M's OpenCL result of 9230 is far above its own average, indicating strong performance in compute workloads relative to its gaming-centric peers.

The GT 555M, by contrast, sits in a less competitive neighborhood. Its nearest rival, the NVIDIA Quadro M5000M, scores 6481, just 0.2% behind. The AMD Radeon Vega 10 Mobile is 0.3% behind at 6476, and the NVIDIA GeForce GTX 670M is 0.3% ahead at 6513. The GT 555M's single OpenCL score of 6493 aligns closely with this cluster, showing it is competitive within its modest tier but nowhere near the GTX 680M's league.

The 42.2% delta in OpenCL is the headline number, and it is not close to being flattering for the older card. The GTX 680M wins the only head-to-head test available, and it wins by a margin that suggests the two GPUs are not merely different in degree but different in class.

Where Each One Wins

The GTX 680M is the clear winner in raw compute performance, as evidenced by its OpenCL score. It also holds advantages in every measurable specification that feeds into gaming and rendering workloads. The 1344 shading units versus 144, the 112 texture mapping units versus 24, and the 32 ROPs versus 16 all point to a GPU that can handle significantly higher geometric complexity and pixel throughput.

The GT 555M has no benchmark wins in the head-to-head data, so its case rests on efficiency and deployment flexibility. Its 35 W TDP is less than half the GTX 680M's 100 W, making it a far more power-frugal option for thin-and-light laptops. The GT 555M also uses a PCIe 2.0 x16 bus interface, which is a standard socket, whereas the GTX 680M requires an MXM-B (3.0) module. For systems designed around a traditional PCIe slot, the GT 555M is the more straightforward integration.

For users prioritizing raw performance in compute or gaming, the GTX 680M wins outright. For users who need a low-power, easily integrated GPU for a portable system, the GT 555M offers a viable path, though its performance ceiling is far lower. The data does not show any workload where the GT 555M outperforms the GTX 680M, so the older card's appeal is entirely about power draw and form factor flexibility.

Architecture Differences

The architectural gap between these two GPUs is generational and profound. The GTX 680M is built on the Kepler architecture using the GK104 chip, fabricated on a 28 nm process at TSMC. The GT 555M uses the Fermi architecture with the GF106 chip, also from TSMC but on a larger 40 nm process. The process node difference alone explains much of the efficiency and density gap.

The transistor counts tell the story. The GTX 680M packs 3,540 million transistors into a 294 mm² die, yielding a transistor density of 12.0M per mm². The GT 555M has 1,170 million transistors on a 238 mm² die, resulting in just 4.9M per mm². The Kepler design is not only more advanced in architecture but also nearly 2.5 times denser in transistor packing.

The memory architecture also differs fundamentally. The GTX 680M uses 4 GB of GDDR5 memory on a 256-bit bus, delivering 115.2 GB/s of bandwidth. The GT 555M uses 1024 MB of DDR3 memory on a 128-bit bus, providing only 28.80 GB/s. This 4x bandwidth advantage for the GTX 680M is critical for high-resolution textures and anti-aliasing.

In terms of compute resources, the GTX 680M's 1344 shading units dwarf the GT 555M's 144. The FP32 throughput is 2.038 TFLOPS versus 339.8 GFLOPS, a sixfold difference. The pixel rate is 21.22 GPixel/s versus 3.540 GPixel/s, and the texture rate is 84.90 GTexel/s versus 14.16 GTexel/s. These are not incremental improvements; they are order-of-magnitude leaps.

The API support is similar, with both cards supporting DirectX 12 (11_0) and OpenGL 4.6. The GTX 680M additionally supports Vulkan 1.2.175, while the GT 555M has no Vulkan support listed. This makes the GTX 680M more future-proof for modern titles that leverage Vulkan.

Specification Differences

The two GPUs differ across nearly every specification in the data pack. The GTX 680M has a base clock of 719 MHz and a boost clock of 758 MHz, while the GT 555M lists no base or boost clock at all. The memory clock is identical at 900 MHz, but the effective data rate differs: 3.6 Gbps for the GTX 680M versus 1800 Mbps for the GT 555M.

Memory configuration is a major differentiator. The GTX 680M offers 4 GB of GDDR5 on a 256-bit bus, while the GT 555M offers 1024 MB of DDR3 on a 128-bit bus. Bandwidth follows accordingly: 115.2 GB/s versus 28.80 GB/s.

Compute resources show the starkest contrast. The GTX 680M has 1344 shading units, 112 TMUs, and 32 ROPs. The GT 555M has 144 shading units, 24 TMUs, and 16 ROPs. The GTX 680M's pixel rate is 21.22 GPixel/s, and its texture rate is 84.90 GTexel/s. The GT 555M manages 3.540 GPixel/s and 14.16 GTexel/s, respectively.

Power and form factor differ significantly. The GTX 680M has a TDP of 100 W and uses an MXM Module with no power connectors, interfacing via MXM-B (3.0). The GT 555M has a 35 W TDP and uses PCIe 2.0 x16. Both GPUs are end-of-life, with the GTX 680M released in June 2012 as part of the GeForce 600M generation, succeeding the GeForce 500M and preceding the GeForce 700M. The GT 555M launched in July 2011 in the GeForce 500M generation, succeeding the GeForce 400M and preceding the GeForce 600M.

The GTX 680M has two benchmark entries (Geekbench Metal at 4815 and Geekbench OpenCL at 9230), while the GT 555M has only one (Geekbench OpenCL at 6493). Neither card lists a launch MSRP, and both have portable-device-dependent display outputs.

FAQ

Q: How much faster is the GTX 680M than the GT 555M in OpenCL?

A: The GTX 680M scores 9230 in Geekbench OpenCL, while the GT 555M scores 6493. This gives the GTX 680M a 42.2% advantage in that benchmark.

Q: Which GPU has more shading units?

A: The GTX 680M has 1344 shading units, compared to 144 on the GT 555M — a 9x difference in raw shader count.

Q: What is the memory bandwidth difference?

A: The GTX 680M delivers 115.2 GB/s over a 256-bit GDDR5 interface, while the GT 555M provides 28.80 GB/s over a 128-bit DDR3 interface, a 4x gap.

Q: Do both GPUs support DirectX 12?

A: Yes, both support DirectX 12 (11_0) and OpenGL 4.6. However, the GTX 680M also supports Vulkan 1.2.175, while the GT 555M has no Vulkan support listed.

Q: Which GPU is more power-efficient?

A: The GT 555M has a 35 W TDP, while the GTX 680M has a 100 W TDP. The GT 555M draws less than half the power, making it more suitable for low-power laptops.

Q: What are the production statuses of these GPUs?

A: Both are marked as end-of-life. The GTX 680M was released in June 2012, and the GT 555M in July 2011.