AMD Radeon RX 6400 vs NVIDIA Quadro K620M Comparison

FAQ

Q: How do the two GPUs compare in overall benchmark scores?

A: The AMD Radeon RX 6400 holds an average benchmark score of 6001, while the NVIDIA Quadro K620M averages 5957. The RX 6400 places in the 35th percentile of all GPUs, slightly ahead of the K620M's 34th percentile.

Q: Is there a direct head-to-head benchmark result available?

A: Yes. In the Geekbench OpenCL test, the RX 6400 scores 32011 versus the Quadro K620M's 5957. That represents a 437.4% advantage for the AMD part, which wins the sole head-to-head comparison.

Q: What are the nearest performance rivals for each card?

A: The RX 6400's closest competitors are the NVIDIA GeForce GTX 770M (avg score 6000, 0% delta), the NVIDIA RTX PRO 6000 Blackwell Server (5996, 0.1% delta), the AMD FirePro W4100 (5987, 0.2% delta), and the NVIDIA Quadro K4000M (5986, 0.3% delta). The Quadro K620M's nearest rivals include the AMD Radeon HD 8730M (5955, 0% delta), the AMD Radeon HD 8750M (5970, -0.2% delta), and the NVIDIA Quadro K4000 (5982, -0.4% delta).

Q: Which card has a higher memory bandwidth?

A: The RX 6400 delivers 128.0 GB/s of bandwidth, a massive jump from the K620M's 16.02 GB/s. The AMD card also uses 4 GB of GDDR6 memory, versus the NVIDIA card's 2 GB of DDR3.

Q: What is the transistor density difference between the two chips?

A: The RX 6400's Navi 24 chip has a transistor density of 50.5M per mm², while the K620M's GM108S has 13.2M per mm². The RX 6400 packs 5,400 million transistors on a 107 mm² die; the K620M has 1,020 million transistors on a 77 mm² die.

Q: Are both cards still in production?

A: No. Both the AMD Radeon RX 6400 and the NVIDIA Quadro K620M are listed as end-of-life products. The RX 6400 was released in January 2022; the K620M was released in February 2015.

Architecture Differences

The AMD Radeon RX 6400 and NVIDIA Quadro K620M come from entirely different architectural generations. The RX 6400 is built on RDNA 2.0, using the Navi 24 chip, and belongs to the Navi II (RX 6000) generation. In contrast, the Quadro K620M uses NVIDIA's Maxwell architecture with the GM108S chip, from the Quadro Kepler-M (Kx200M) generation. This generational gap is reflected in the process technology: the RX 6400 uses a 6 nm TSMC process, while the K620M is fabricated on a 28 nm TSMC node. That process difference yields a stark transistor density gap — 50.5M per mm² for the AMD chip versus just 13.2M per mm² for the NVIDIA chip.

The memory subsystems are fundamentally different as well. The RX 6400 has 4 GB of GDDR6 memory on a 64-bit bus, delivering 128.0 GB/s of bandwidth. The K620M offers 2 GB of DDR3 memory on the same 64-bit bus width, but only achieves 16.02 GB/s. The clock speeds tell a similar story: the RX 6400 has a base clock of 1923 MHz and a boost of 2321 MHz, while the K620M runs at a 1029 MHz base and 1124 MHz boost. The AMD card also has a game clock of 2039 MHz. Memory clocks differ dramatically too — the RX 6400 runs at 2000 MHz (16 Gbps effective), while the K620M runs at 1001 MHz (2 Gbps effective).

Compute resources are heavily skewed toward the AMD card. The RX 6400 has 768 shading units, 48 TMUs, 32 ROPs, and 12 ray tracing cores. The K620M has 384 shading units, 16 TMUs, and 8 ROPs — with no ray tracing cores at all. The RX 6400 also supports DirectX 12 Ultimate (12_2), while the K620M only supports DirectX 12 (11_0). Both cards support OpenGL 4.6 and Vulkan 1.4. The RX 6400 does not list FP16 support, while the K620M lists FP16 as null; the RX 6400's FP32 output is 3.565 TFLOPS versus the K620M's 863.2 GFLOPS.

Physical and power characteristics differ as well. The RX 6400 has a TDP of 53 W and is a single-slot card with no power connectors, suggesting a 250 W PSU. The K620M has a 30 W TDP and is an MXM Module form factor with no power connectors and no suggested PSU. The RX 6400 uses a PCIe 4.0 x4 bus interface and has 1x HDMI 2.1 plus 1x DisplayPort 1.4a outputs. The K620M uses an MXM-A (3.0) interface and its display outputs are described as "Portable Device Dependent."

Head-to-Head Benchmarks

The single direct comparison available in the data is the Geekbench OpenCL test, and the result is not close. The AMD Radeon RX 6400 scores 32011, while the NVIDIA Quadro K620M scores 5957. That is a 437.4% delta in favor of the RX 6400 — a dominant margin that underscores the massive generational and architectural gap between the two cards. The RX 6400 wins the only head-to-head benchmark, giving it a 1-0 record over the K620M.

Context from the broader benchmark suite reinforces this picture. The RX 6400's average benchmark score of 6001 places it just ahead of the K620M's 5957 average, though that gap is small. The percentile rankings are close as well: 35th versus 34th. However, the RX 6400 has a much wider set of benchmark results. It scores 7673 in Passmark G3D, 2812 in Passmark GPU Compute, 722 in Passmark G2D, and 176 in 3DMark Steel Nomad DX12. It also posts 16372 in Geekbench Vulkan and 32011 in Geekbench OpenCL. The K620M only has a single Geekbench OpenCL result of 5957.

Looking at the RX 6400's nearest rivals, the data shows it sits in a tight cluster around the 6000-point mark. The GeForce GTX 770M is equal at 6000 (0% delta), the RTX PRO 6000 Blackwell Server is 0.1% behind, and the FirePro W4100 and Quadro K4000M trail by 0.2% and 0.3% respectively. The K620M's rivals are similarly bunched: the Radeon HD 8730M is at 5955 (0% delta), the Radeon HD 8750M is 0.2% ahead, and the Quadro K4000 is 0.4% ahead. The Intel UHD Graphics 730 trails by 0.5%. In raw average score, the RX 6400 is only 0.7% ahead of the K620M, yet the OpenCL head-to-head shows a 437.4% gap — a discrepancy that highlights how differently the two cards perform across workloads.

The RX 6400 also has a broader feature set reflected in its benchmark coverage. It shows results across DirectX 9, 10, 11, and 12 tests, with Passmark scores of 93, 54, 70, and 30 respectively. The K620M lacks these results entirely. This suggests the RX 6400 is capable of running a wider range of modern workloads, consistent with its DirectX 12 Ultimate support and ray tracing cores.

The Verdict

For anyone choosing between these two cards, the data points decisively to the AMD Radeon RX 6400. It wins the only head-to-head benchmark by 437.4%, has more than double the shading units (768 versus 384), and offers eight times the memory bandwidth (128.0 GB/s versus 16.02 GB/s). Its 6 nm process node, 5,400 million transistors, and 50.5M per mm² density put it in a different technological class than the 28 nm, 1,020 million transistor Maxwell chip in the K620M.

The RX 6400 is the pick for anyone needing modern API support. It handles DirectX 12 Ultimate, includes ray tracing cores, and has a 4 GB GDDR6 frame buffer. The K620M, by contrast, stops at DirectX 12 (11_0), has no ray tracing hardware, and only 2 GB of DDR3. The RX 6400 also has a higher pixel rate (74.27 GPixel/s versus 8.992 GPixel/s) and texture rate (111.4 GTexel/s versus 17.98 GTexel/s), making it substantially faster in fill-rate-bound scenarios.

The Quadro K620M does have one advantage: power consumption. Its 30 W TDP is lower than the RX 6400's 53 W, and its MXM Module form factor with portable-device-dependent outputs suggests it was designed for laptops or compact mobile workstations. The RX 6400 is a single-slot desktop card with no power connectors but a 250 W suggested PSU. If the requirement is a low-power mobile GPU, the K620M may fit a specific niche. However, from a pure performance standpoint, the RX 6400 is the clear winner across every measured metric where both have data.

The benchmark cluster around both cards shows they sit in similar overall performance tiers — both are around the 34th-35th percentile of all GPUs, and their nearest rivals all fall within a 0.5% delta. Yet the RX 6400's much higher OpenCL score and broader feature set make it the more capable and future-proof option. The K620M's single benchmark result of 5957 is its only data point, which limits its comparability. Users who need ray tracing, higher compute throughput, or modern API support should choose the RX 6400. Those constrained by power or form factor and working with legacy software may consider the K620M, but the data offers little reason to prefer it otherwise.

Specification Differences

| Specification | AMD Radeon RX 6400 | NVIDIA Quadro K620M |

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

| Architecture | RDNA 2.0 | Maxwell |

| Process Node | 6 nm | 28 nm |

| Transistors | 5,400 million | 1,020 million |

| Die Size | 107 mm² | 77 mm² |

| Transistor Density | 50.5M / mm² | 13.2M / mm² |

| Base Clock | 1923 MHz | 1029 MHz |

| Boost Clock | 2321 MHz | 1124 MHz |

| Memory Size | 4 GB | 2 GB |

| Memory Type | GDDR6 | DDR3 |

| Memory Bus Width | 64 bit | 64 bit |

| Memory Bandwidth | 128.0 GB/s | 16.02 GB/s |

| Shading Units | 768 | 384 |

| TMUs | 48 | 16 |

| ROPs | 32 | 8 |

| RT Cores | 12 | None |

| Pixel Rate | 74.27 GPixel/s | 8.992 GPixel/s |

| Texture Rate | 111.4 GTexel/s | 17.98 GTexel/s |

| FP32 | 3.565 TFLOPS | 863.2 GFLOPS |

| FP16 | 7.130 TFLOPS (2:1) | Not listed |

| TDP | 53 W | 30 W |

| Slot Width | Single-slot | MXM Module |

| Power Connectors | None | None |

| Suggested PSU | 250 W | Not listed |

| Bus Interface | PCIe 4.0 x4 | MXM-A (3.0) |

| Display Outputs | 1x HDMI 2.1, 1x DisplayPort 1.4a | Portable Device Dependent |

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

| Release Date | 2022-01-18 | 2015-02-28 |