AMD Radeon RX 6400 vs NVIDIA Quadro K4000 Comparison

The AMD Radeon RX 6400 and NVIDIA Quadro K4000 represent two vastly different eras of GPU design, and the benchmark data reflects this chasm. The RX 6400 holds a commanding lead in every head-to-head comparison, with a 369.6% advantage in Geekbench OpenCL and a 135.1% advantage in Geekbench Vulkan. These are not marginal gains; they are generational leaps that redefine what a user can expect from a competing product in this segment.

Head-to-Head Benchmarks

The most striking result is in the Geekbench OpenCL test, where the AMD Radeon RX 6400 scores 32011 against the NVIDIA Quadro K4000’s 6816. This 369.6% delta is not just a win; it is a complete obliteration of the older card’s compute capability. For any workload leveraging OpenCL—be it rendering, scientific simulation, or data processing—the RX 6400 delivers nearly four times the throughput. The data suggests that the Quadro K4000’s Kepler architecture, while professional-grade in its time, simply cannot compete with the raw compute density of RDNA 2.0.

In the Geekbench Vulkan test, the RX 6400 again dominates with a score of 16372 versus 6964, a 135.1% advantage. Vulkan is a low-overhead API that scales well with modern hardware, and the results show the RX 6400’s architecture is far better suited to it. The K4000’s Vulkan support is listed as 1.2.175, which is functional, but its older design limits its ability to exploit the API’s parallelism. The RX 6400’s score here is more than double, indicating a smoother experience in modern games and compute applications that rely on Vulkan.

Notably, the head-to-head data shows the AMD card winning both tests, with 2 wins and 0 losses. There is no benchmark where the Quadro K4000 outperforms the RX 6400 in this comparison set. This is a one-sided affair, and the magnitude of the deltas suggests that the K4000 is not just slower but fundamentally outclassed in these specific metrics.

Architecture Differences

The architectural gap between these two cards is immense. The AMD Radeon RX 6400 is built on the RDNA 2.0 architecture, using a 6 nm process at TSMC, packing 5,400 million transistors into a 107 mm² die. This yields a transistor density of 50.5M per mm², a figure that highlights the efficiency of modern manufacturing. In contrast, the NVIDIA Quadro K4000 uses the Kepler architecture on a 28 nm process, also at TSMC, with 2,540 million transistors spread across a much larger 221 mm² die, resulting in a density of just 11.5M per mm².

The memory subsystems tell a similar story. The RX 6400 features 4 GB of GDDR6 memory on a 64-bit bus, delivering 128.0 GB/s of bandwidth. The K4000 has 3 GB of GDDR5 on a 192-bit bus, achieving 134.8 GB/s. While the K4000 has a slight bandwidth advantage, the RX 6400’s newer memory type and higher effective speed (16 Gbps versus 5.6 Gbps) compensate, and the compute capabilities dwarf the older card.

Core counts also differ. Both have 768 shading units, but the RX 6400 pairs them with 48 TMUs and 32 ROPs, while the K4000 has 64 TMUs and 24 ROPs. The RX 6400 also includes 12 ray tracing cores, a feature entirely absent from the K4000. This is a critical differentiator, as the RX 6400 supports DirectX 12 Ultimate (12_2), while the K4000 only reaches DirectX 12 (11_0). The RX 6400’s pixel rate of 74.27 GPixel/s and texture rate of 111.4 GTexel/s dwarf the K4000’s 12.96 GPixel/s and 51.84 GTexel/s, respectively.

Power efficiency is another stark contrast. The RX 6400 has a TDP of 53 W and requires no power connectors, while the K4000 draws 80 W and needs a 6-pin connector. Both suggest a 250 W PSU, but the RX 6400 achieves far more performance per watt, a direct result of the 6 nm process versus 28 nm.

FAQ

Q: Which card has higher compute performance in OpenCL?

A: The AMD Radeon RX 6400 scores 32011 in Geekbench OpenCL, which is 369.6% higher than the NVIDIA Quadro K4000’s 6816. This indicates the RX 6400 is roughly four times faster in OpenCL compute tasks.

Q: Does the NVIDIA Quadro K4000 support ray tracing?

A: No. The K4000 has no ray tracing cores listed, and its DirectX support is limited to 12 (11_0). The AMD Radeon RX 6400 includes 12 ray tracing cores and supports DirectX 12 Ultimate (12_2), enabling hardware-accelerated ray tracing.

Q: How do the memory bandwidths compare?

A: The K4000 has a 192-bit bus with 3 GB of GDDR5, providing 134.8 GB/s. The RX 6400 uses a 64-bit bus with 4 GB of GDDR6, providing 128.0 GB/s. The K4000 has a slight bandwidth edge, but the RX 6400’s faster effective memory speed (16 Gbps vs 5.6 Gbps) and newer type compensate.

Q: What is the process node difference?

A: The RX 6400 is built on a 6 nm TSMC process, while the K4000 uses a 28 nm TSMC process. This allows the RX 6400 to pack 50.5M transistors per mm², compared to 11.5M per mm² for the K4000.

Q: Which card is more power-efficient based on the data?

A: The RX 6400 has a TDP of 53 W and requires no external power connectors, while the K4000 has an 80 W TDP and needs a 6-pin connector. Given the RX 6400’s far higher benchmark scores, it delivers significantly more performance per watt.

Q: Are there any benchmarks where the K4000 wins?

A: In the head-to-head data provided, the K4000 wins zero tests. The RX 6400 wins both Geekbench OpenCL and Vulkan tests. The K4000 does have a Geekbench Metal score of 4166, but that test is not available for the RX 6400.

The Verdict

The data is unambiguous. The AMD Radeon RX 6400 is the superior performer in every benchmark where both cards are tested. Its 369.6% lead in OpenCL and 135.1% lead in Vulkan are not just wins; they are decisive victories that reflect a fundamental architectural advantage. The RX 6400’s RDNA 2.0 architecture, 6 nm process, and modern features like ray tracing make it a far more capable card for contemporary workloads.

The NVIDIA Quadro K4000, while a professional card from its era, is severely outdated. Its 28 nm process and Kepler architecture limit its compute and graphics capabilities. The K4000’s only potential advantage is its slightly higher memory bandwidth (134.8 GB/s vs 128.0 GB/s), but this does not translate into any benchmark win. For any user choosing between these two, the RX 6400 is the clear choice based on performance data alone. The K4000’s higher launch MSRP of 1,269 USD versus the RX 6400’s 159 USD further underscores the RX 6400’s dominance, though pricing is not a factor in performance analysis.

Specification Differences

The two cards differ on nearly every specification. The RX 6400 uses a 6 nm process, while the K4000 uses 28 nm. Transistor counts are 5,400 million versus 2,540 million, with die sizes of 107 mm² and 221 mm², respectively. Memory differs: 4 GB GDDR6 on a 64-bit bus for the RX 6400, versus 3 GB GDDR5 on a 192-bit bus for the K4000. Bandwidth is close, but the RX 6400 has 128.0 GB/s, and the K4000 has 134.8 GB/s.

The RX 6400 has a base clock of 1923 MHz and a boost of 2321 MHz, while the K4000 has no listed clock speeds. The RX 6400 includes 12 ray tracing cores; the K4000 has none. Pixel rates are 74.27 GPixel/s vs 12.96 GPixel/s, and texture rates are 111.4 GTexel/s vs 51.84 GTexel/s. FP32 compute is 3.565 TFLOPS for the RX 6400 versus 1,244.2 GFLOPS for the K4000. TDPs are 53 W and 80 W, with the RX 6400 requiring no power connectors and the K4000 needing a 6-pin. Bus interfaces are PCIe 4.0 x4 and PCIe 2.0 x16. Display outputs are also different: 1x HDMI 2.1 and 1x DisplayPort 1.4a versus 1x DVI and 2x DisplayPort 1.2. The K4000 has physical dimensions of 241 mm in length and 111 mm in height, while the RX 6400 has none listed.

Where Each One Wins

The AMD Radeon RX 6400 wins in compute-heavy applications. Its OpenCL score of 32011 is 369.6% higher, making it the obvious pick for tasks like rendering, video encoding, or scientific calculations that utilize OpenCL. Its Vulkan score of 16372 is 135.1% higher, indicating it is also better for modern games and applications that leverage this low-overhead API. The RX 6400’s support for DirectX 12 Ultimate and ray tracing further solidifies its position for gaming and future-proofed workloads.

The NVIDIA Quadro K4000 has no benchmark wins in the head-to-head data. However, its professional lineage (Quadro Kepler generation) might suggest stability in legacy professional applications, but the data does not support any performance advantage. Its only potentially favorable field is memory bandwidth, where it edges out the RX 6400 by 6.8 GB/s, but this does not translate into any measured performance win. The K4000’s 192-bit bus could theoretically offer better performance in memory-bound scenarios, but the benchmark results show this is not the case in practice. For any use case where the two are compared, the RX 6400 is the recommended choice based on the available data.