NVIDIA GeForce GT 555M vs NVIDIA Quadro K620 Comparison

The NVIDIA GeForce GT 555M and NVIDIA Quadro K620 are both end-of-life GPUs from NVIDIA, but they serve very different purposes. The GT 555M is a mobile graphics chip from the GeForce 500M generation, built for laptops in 2011, while the Quadro K620 is a desktop professional workstation card from 2014, designed for CAD and content creation. Despite the age gap, the benchmark data places them in a similar performance tier, making a direct comparison surprisingly meaningful. The core question is whether the older mobile chip’s raw compute edge or the newer workstation card’s feature set and efficiency wins the day.

Where Each One Wins

The benchmark results split the two GPUs into distinct use-case categories. The GeForce GT 555M, with its GeForce 500M generation branding, is explicitly a mobile solution—its display output is listed as "Portable Device Dependent," meaning it is designed to be integrated into laptops where it delivers graphics for gaming and general consumer workloads. Its single benchmark score comes from Geekbench OpenCL, where it posts 6,493 points. This places it in the 37th percentile of all GPUs, which is a modest standing, but its nearest rivals include the NVIDIA GeForce GTX 670M (a higher-tier mobile card) and the Intel UHD Graphics P750 (an integrated solution). The data suggests the GT 555M is competitive in its mobile niche, trading blows with other laptop-class GPUs.

The Quadro K620, on the other hand, is a professional workstation GPU. It is a single-slot, 160 mm long card with outputs for 1x DVI and 1x DisplayPort 1.2, which are typical for a desktop professional environment. Its production status is end-of-life, but its release date of 2014 places it three years newer than the GT 555M. The K620 wins the head-to-head OpenCL benchmark with a score of 6,693, which is 3% higher than the GT 555M’s 6,493. It also has a Vulkan benchmark score of 5,870, a test the GT 555M does not have, indicating broader API support for modern workloads. Its percentileVsAllGpus is 36, essentially tied with the GT 555M, but its nearest rivals include the NVIDIA GeForce RTX 5070 Ti SUPER and RTX 4070 Ti SUPER AD102—modern, high-end cards—which highlights how close its average score is to much newer hardware.

Architecture Differences

The architectural gap between these two is substantial. The GT 555M is built on the Fermi architecture, using the GF106 chip, fabricated on a 40 nm process at TSMC. It packs 1,170 million transistors into a 238 mm² die, yielding a transistor density of 4.9M per mm². The K620 uses the Maxwell architecture with the GM107 chip, also from TSMC, but on a newer 28 nm process. It contains 1,870 million transistors on a much smaller 148 mm² die, giving a transistor density of 12.6M per mm²—more than double the density of the Fermi chip. This is a clear sign of architectural efficiency improvements, as Maxwell packs more compute into less silicon.

The shading units tell a similar story. The GT 555M has 144 shading units, while the K620 has 384, a massive increase in parallel compute capacity. Both have 24 texture mapping units (TMUs) and 16 raster output units (ROPs), so the texture and pixel handling capabilities are identical in count. However, the raw throughput differs: the GT 555M delivers 3.540 GPixel/s pixel rate and 14.16 GTexel/s texture rate, while the K620 delivers 17.98 GPixel/s and 26.98 GTexel/s. The K620’s boost clock of 1,124 MHz (base 1,058 MHz) helps drive these figures, whereas the GT 555M has no listed base or boost clock, only a memory clock of 900 MHz (1,800 Mbps effective). Memory is identical in type (DDR3), bus width (128 bit), and bandwidth (28.80 GB/s), but the K620 doubles the capacity to 2 GB versus the GT 555M’s 1 GB.

Head-to-Head Benchmarks

The only direct benchmark comparison available is Geekbench OpenCL, where the Quadro K620 wins decisively but not overwhelmingly. The K620 scores 6,693, while the GT 555M scores 6,493, a delta of -3% from the GT 555M’s perspective. This 200-point gap is small in absolute terms, but it represents a real performance advantage for the K620 in compute workloads. In FP32 floating-point performance, the gap is much larger: the K620 delivers 863.2 GFLOPS, while the GT 555M delivers 339.8 GFLOPS. That is roughly 2.5 times the compute throughput, a significant margin that the OpenCL score does not fully reflect. The K620’s pixel rate is also over five times higher (17.98 vs 3.540 GPixel/s), and its texture rate is nearly double (26.98 vs 14.16 GTexel/s).

The GT 555M’s nearest rival data shows it is within 0.3% of the NVIDIA Quadro M5000M and AMD Radeon Vega 10 Mobile, and 0.9% behind the Intel UHD Graphics P750. This indicates that the GT 555M is a mid-tier mobile part, sitting in a crowded field of similar-performance GPUs. The K620’s nearest rivals are more surprising: it is 0.2% ahead of the NVIDIA GeForce RTX 5070 Ti SUPER and RTX 4070 Ti SUPER AD102, and 0.7-0.8% behind the AMD Radeon R7 M350 and Radeon Pro WX 4100. This suggests that the K620’s average benchmark score of 6,282 is remarkably competitive with much newer and higher-end GPUs, even if its single OpenCL score is slightly higher at 6,693.

FAQ

Q: Which GPU has the higher OpenCL benchmark score?

A: The NVIDIA Quadro K620 wins the Geekbench OpenCL test with a score of 6,693, compared to the GeForce GT 555M’s 6,493, a 3% difference.

Q: What is the architectural generation difference between the two?

A: The GT 555M uses the Fermi architecture (chip GF106) on a 40 nm process, while the K620 uses Maxwell (chip GM107) on a 28 nm process. The K620 also has a higher transistor density at 12.6M per mm² versus 4.9M per mm².

Q: How do their memory specifications compare?

A: Both use DDR3 memory with a 128-bit bus and 28.80 GB/s bandwidth. The GT 555M has 1,024 MB, while the K620 doubles this to 2 GB.

Q: Does the Quadro K620 support Vulkan?

A: Yes, the K620 lists Vulkan 1.4 support and has a Geekbench Vulkan score of 5,870. The GT 555M has no Vulkan score or API listing in the data.

Q: What is the TDP difference?

A: The GT 555M is rated at 35 W, while the K620 is rated at 45 W. The K620 also suggests a 200 W PSU, though it requires no power connectors.

Q: Which GPU has more shading units?

A: The K620 has 384 shading units, while the GT 555M has 144. The K620 also has significantly higher FP32 performance at 863.2 GFLOPS versus 339.8 GFLOPS.

Specification Differences

| Specification | NVIDIA GeForce GT 555M | NVIDIA Quadro K620 |

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

| Architecture | Fermi | Maxwell |

| Chip | GF106 | GM107 |

| Process Node | 40 nm | 28 nm |

| Transistors | 1,170 million | 1,870 million |

| Die Size | 238 mm² | 148 mm² |

| Transistor Density | 4.9M / mm² | 12.6M / mm² |

| Base Clock | — | 1058 MHz |

| Boost Clock | — | 1124 MHz |

| Memory Size | 1024 MB | 2 GB |

| Shading Units | 144 | 384 |

| Pixel Rate | 3.540 GPixel/s | 17.98 GPixel/s |

| Texture Rate | 14.16 GTexel/s | 26.98 GTexel/s |

| FP32 | 339.8 GFLOPS | 863.2 GFLOPS |

| TDP | 35 W | 45 W |

| Slot Width | — | Single-slot |

| Power Connectors | — | None |

| Suggested PSU | — | 200 W |

| Display Outputs | Portable Device Dependent | 1x DVI, 1x DisplayPort 1.2 |

| Vulkan Support | — | 1.4 |

| Dimensions (Length) | — | 160 mm / 6.3 inches |

| Dimensions (Height) | — | 69 mm / 2.7 inches |

| Release Date | 2011-07-01 | 2014-07-21 |

| Generation | GeForce 500M | Quadro Kepler (Kx200) |

| Predecessor | GeForce 400M | Quadro Fermi |

| Successor | GeForce 600M | Quadro Maxwell |

The Verdict

The data points to a clear winner for raw compute: the Quadro K620. It wins the only head-to-head benchmark, has more than double the shading units, and delivers 863.2 GFLOPS versus the GT 555M’s 339.8 GFLOPS. Its 2 GB memory capacity and support for Vulkan 1.4 also make it more capable for modern software environments. The K620’s nearest rivals include GPUs like the RTX 5070 Ti SUPER, which underscores that its performance is still relevant even years after its release.

The GT 555M, however, is not without its own merits. Its 35 W TDP is lower than the K620’s 45 W, which is critical for mobile devices. Its display output is "Portable Device Dependent," meaning it is designed for laptops where the K620’s desktop form factor (single-slot, 160 mm length, DVI/DisplayPort outputs) would be impossible. The GT 555M’s 37th percentile ranking is also slightly higher than the K620’s 36th, indicating that in the broader GPU landscape, it holds a marginally better position relative to all other GPUs.

For a laptop user needing a legacy mobile GPU, the GT 555M is the only option of the two, given the K620’s desktop-only design. For a desktop workstation user, the K620 is the superior choice on every measurable compute metric—OpenCL score, FP32, pixel rate, and texture rate—and its 2 GB memory is double the GT 555M’s. The verdict is straightforward: the Quadro K620 is the stronger GPU in performance, but the GT 555M wins on power efficiency and portability. The choice depends entirely on the form factor and workload, but for pure compute, the K620 is the data-backed winner.