GPU Comparison

The NVIDIA Quadro K620 and AMD Radeon RX 6400 represent two very different eras of GPU design. The data shows a decisive split: the Radeon RX 6400 wins every head-to-head benchmark in the pack, but the Quadro K620 holds its own in overall percentile ranking. This page breaks down where each card wins, why the architectures differ so fundamentally, and what the benchmark scores actually mean for potential users.

Where Each One Wins

The AMD Radeon RX 6400 is the clear winner in raw compute performance. In the two shared benchmarks, it dominates the Quadro K620 by a massive margin. The Radeon's Geekbench OpenCL score of 32,011 is roughly 4.8 times higher than the Quadro's 6,693. Similarly, in Geekbench Vulkan, the Radeon scores 16,372 versus the Quadro's 5,870, a lead of nearly 2.8 times. For any workload that leverages general-purpose GPU compute or modern graphics APIs, the RX 6400 is the only viable choice between the two.

The Quadro K620, however, shows a different kind of strength. Its average benchmark score of 6,282 places it in the 36th percentile of all GPUs, slightly higher than the RX 6400's 35th percentile with an average score of 6,001. This suggests that while the RX 6400 excels in the specific tests where they overlap, the Quadro's overall profile across a broader range of benchmarks is marginally more consistent. The Quadro's nearest rivals include the GeForce RTX 5070 Ti SUPER and RTX 4070 Ti SUPER AD102, both with average scores of 6,270 (a 0.2% delta). This clustering indicates that the K620's performance level, while old, is not an outlier in the database's historical context.

The RX 6400's wins are not limited to compute. In the Passmark suite, it posts scores of 7,673 in G3D, 2,812 in GPU Compute, and 722 in G2D. These are standalone figures, but they reinforce the pattern: the Radeon is built for throughput, while the Quadro is a legacy product whose strengths lie elsewhere—likely in its driver certification and stability for professional applications, though the data does not quantify that directly.

Architecture Differences

The architectural gap between these two cards is generational. The Quadro K620 is built on NVIDIA's Maxwell architecture (chip GM107) using a 28 nm process at TSMC. It packs 1,870 million transistors into a 148 mm² die, yielding a transistor density of 12.6 million per mm². The RX 6400, by contrast, uses AMD's RDNA 2.0 architecture (chip Navi 24) on a 6 nm process, also at TSMC. It contains 5,400 million transistors on a smaller 107 mm² die, achieving a density of 50.5 million per mm². This is a fourfold increase in density, explaining the massive performance per area advantage.

Clock speeds tell a similar story. The Quadro runs at a base of 1058 MHz with a boost of 1124 MHz. The RX 6400 starts at 1923 MHz base, boosts to 2321 MHz, and has a game clock of 2039 MHz. Even the memory subsystem is a generation apart: the Quadro uses 2 GB of DDR3 on a 128-bit bus, delivering 28.80 GB/s of bandwidth. The Radeon uses 4 GB of GDDR6 on a 64-bit bus, but achieves 128.0 GB/s—over four times the bandwidth despite half the bus width, thanks to much faster memory clocks (16 Gbps effective versus 1800 Mbps effective).

Compute resources are also starkly different. The Quadro has 384 shading units, 24 TMUs, and 16 ROPs. The RX 6400 doubles these: 768 shading units, 48 TMUs, and 32 ROPs. The Radeon also features 12 ray tracing cores, something the Quadro lacks entirely. Pixel rate jumps from 17.98 GPixel/s to 74.27 GPixel/s, and texture rate from 26.98 GTexel/s to 111.4 GTexel/s. FP32 performance is 863.2 GFLOPS for the Quadro versus 3.565 TFLOPS for the Radeon—a fourfold increase. The Radeon also supports FP16 at 7.130 TFLOPS (2:1 ratio), while the Quadro has no listed FP16 capability.

The bus interface differs too: the Quadro uses PCIe 2.0 x16, while the RX 6400 uses PCIe 4.0 x4. This means the Radeon relies on a narrower but faster link, which can be a bottleneck in some scenarios, but the data shows it does not hamper its benchmark performance. Power consumption is modest for both, at 45 W for the Quadro and 53 W for the Radeon, with neither requiring external power connectors.

Head-to-Head Benchmarks

The head-to-head data is unambiguous: the AMD Radeon RX 6400 wins both shared tests. In Geekbench OpenCL, the Radeon scores 32,011 against the Quadro's 6,693, a delta of -79.1% from the Radeon's perspective (meaning the Quadro is 79.1% slower). In Geekbench Vulkan, the Radeon scores 16,372 versus the Quadro's 5,870, a delta of -64.1%. These are not marginal differences; they represent a complete generational leap.

To put these numbers in context, consider the Radeon's nearest rivals. Its average score of 6,001 places it alongside the GeForce GTX 770M (6,000, 0% delta), the RTX PRO 6000 Blackwell Server (5,996, 0.1% delta), and the AMD FirePro W4100 (5,987, 0.2% delta). The Quadro K620, with an average of 6,282, sits near the GeForce RTX 5070 Ti SUPER and RTX 4070 Ti SUPER AD102 (both 6,270, 0.2% delta). This is a curious result: the K620's average is slightly higher than the RX 6400's, despite losing both head-to-head tests. This is likely because the average includes a different mix of benchmarks—the Quadro has only two listed tests (both Geekbench), while the Radeon has ten, including Passmark tests where it scores lower (e.g., 30 in DirectX 12, 54 in DirectX 10).

The biggest win for the Radeon is in the OpenCL test, where its 32,011 score is a staggering 378% higher than the Quadro's 6,693. The Vulkan test shows a 179% advantage. These are the only two direct comparisons available, but they are decisive. For any application that uses OpenCL or Vulkan—common in compute, rendering, and modern gaming—the RX 6400 is categorically superior.

The Verdict

The data supports a clear conclusion: the AMD Radeon RX 6400 is the superior card for virtually any modern workload. It wins both head-to-head benchmarks by margins of 64% to 79%, offers four times the memory (4 GB vs 2 GB) with over four times the bandwidth, and provides modern features like ray tracing and FP16 support. Its 3.565 TFLOPS of FP32 performance dwarfs the Quadro's 863.2 GFLOPS. For gaming, compute, or any GPU-accelerated task, the RX 6400 is the only rational choice.

The NVIDIA Quadro K620, however, has a niche. Its average benchmark score (6,282) is slightly higher than the Radeon's (6,001), and it sits in a higher percentile (36th vs 35th). This suggests that in legacy applications that do not leverage modern APIs or compute features, the Quadro may perform relatively better than its raw specs imply. The K620 also has a longer track record (released 2014-07-21 versus 2022-01-18) and a professional Quadro lineage (predecessor Quadro Fermi, successor Quadro Maxwell), which historically implies certified drivers for professional software—though this is not quantified in the data.

That said, the Quadro's advantages are marginal and contextual. Its single-slot design and 45 W TDP (versus 53 W for the Radeon) make it slightly more power-efficient, and its PCIe 2.0 x16 interface is wider, though slower. But the Radeon's raw performance advantages are so large that they overwhelm these minor trade-offs. For anyone choosing between these two today, the RX 6400 is the pick unless specific legacy software compatibility dictates otherwise.

FAQ

Q: Which card has better OpenCL performance?

A: The AMD Radeon RX 6400 scores 32,011 in Geekbench OpenCL, versus the NVIDIA Quadro K620's 6,693. The Radeon is 79.1% faster in this test.

Q: How much memory does each card have?

A: The Quadro K620 has 2 GB of DDR3 memory on a 128-bit bus, while the RX 6400 has 4 GB of GDDR6 on a 64-bit bus. The Radeon's bandwidth is 128.0 GB/s versus 28.80 GB/s.

Q: Does the RX 6400 support ray tracing?

A: Yes, the RX 6400 has 12 ray tracing cores. The Quadro K620 has no ray tracing cores listed.

Q: Which card has a higher average benchmark score?

A: The Quadro K620 has an average score of 6,282, slightly higher than the RX 6400's 6,001. However, the Radeon wins every head-to-head test.

Q: What is the power consumption difference?

A: The Quadro K620 has a TDP of 45 W, while the RX 6400 has a TDP of 53 W. Both are single-slot cards with no external power connectors.

Q: Which card is newer?

A: The RX 6400 was released on 2022-01-18, while the Quadro K620 was released on 2014-07-21. Both are end-of-life products.

Specification Differences

The following table lists only the fields where the two cards differ, based on the data pack.

| Field | NVIDIA Quadro K620 | AMD Radeon RX 6400 |

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

| Manufacturer | NVIDIA | AMD |

| Chip | GM107 | Navi 24 |

| Architecture | Maxwell | RDNA 2.0 |

| Generation | Quadro Kepler (Kx200) | Navi II (RX 6000) |

| Process Node | 28 nm | 6 nm |

| Transistors | 1,870 million | 5,400 million |

| Die Size | 148 mm² | 107 mm² |

| Transistor Density | 12.6M / mm² | 50.5M / mm² |

| Base Clock | 1058 MHz | 1923 MHz |

| Boost Clock | 1124 MHz | 2321 MHz |

| Game Clock | N/A | 2039 MHz |

| Memory Clock | 900 MHz / 1800 Mbps effective | 2000 MHz / 16 Gbps effective |

| Memory Size | 2 GB | 4 GB |

| Memory Type | DDR3 | GDDR6 |

| Memory Bus Width | 128 bit | 64 bit |

| Memory Bandwidth | 28.80 GB/s | 128.0 GB/s |

| Shading Units | 384 | 768 |

| TMUs | 24 | 48 |

| ROPs | 16 | 32 |

| Ray Tracing Cores | N/A | 12 |

| Pixel Rate | 17.98 GPixel/s | 74.27 GPixel/s |

| Texture Rate | 26.98 GTexel/s | 111.4 GTexel/s |

| FP32 Performance | 863.2 GFLOPS | 3.565 TFLOPS |

| FP16 Performance | N/A | 7.130 TFLOPS (2:1) |

| TDP | 45 W | 53 W |

| Suggested PSU | 200 W | 250 W |

| Bus Interface | PCIe 2.0 x16 | PCIe 4.0 x4 |

| Display Outputs | 1x DVI, 1x DisplayPort 1.2 | 1x HDMI 2.1, 1x DisplayPort 1.4a |

| DirectX Support | 12 (11_0) | 12 Ultimate (12_2) |

| Release Date | 2014-07-21 | 2022-01-18 |

| Predecessor | Quadro Fermi | Navi |

| Successor | Quadro Maxwell | Navi III |

| Launch MSRP | N/A | 159 USD |