AMD Radeon RX 6600 vs NVIDIA RTX A4000 Mobile Comparison

The Verdict

The NVIDIA RTX A4000 Mobile and AMD Radeon RX 6600 are both end-of-life products, but they serve fundamentally different purposes. The A4000 Mobile is a professional mobile workstation GPU built on the Ampere architecture, while the RX 6600 is a desktop gaming card from the Radeon RX 6000 series. The data shows the A4000 Mobile wins the overall benchmark head-to-head in compute-heavy workloads by a massive margin, but the RX 6600 takes more individual tests, particularly in legacy DirectX and 2D performance. If the priority is raw compute throughput, especially OpenCL performance, the A4000 Mobile is the clear choice. If the priority is broader compatibility with older DirectX APIs and faster 2D operations, the RX 6600 has the edge. The A4000 Mobile also sits higher in the overall GPU percentile ranking at 66, versus 63 for the RX 6600, and its average benchmark score of 21379 is about 12.3% higher than the RX 6600's 19036.

FAQ

Q: Which GPU has the higher average benchmark score?

A: The NVIDIA RTX A4000 Mobile has an average benchmark score of 21379, compared to the AMD Radeon RX 6600's 19036. That is a lead of roughly 12.3% for the NVIDIA part.

Q: How do the two compare in Geekbench OpenCL performance?

A: The A4000 Mobile scores 97178 in Geekbench OpenCL, while the RX 6600 scores 28850. This gives the NVIDIA card a 236.8% advantage, its largest single-test win in the head-to-head comparison.

Q: Which GPU performs better in DirectX 11 and DirectX 9 tests?

A: The AMD Radeon RX 6600 wins both. In Passmark DirectX 11, it scores 152 versus 127 for the A4000 Mobile, a 16.4% difference. In Passmark DirectX 9, it scores 197 versus 157, a 20.3% difference.

Q: What is the memory bandwidth difference between the two?

A: The A4000 Mobile has a 256-bit memory bus with 384.0 GB/s bandwidth, while the RX 6600 has a 128-bit bus with 224.0 GB/s bandwidth. The NVIDIA card offers about 71.4% more memory bandwidth.

Q: Which card has the higher boost clock?

A: The AMD Radeon RX 6600 has a boost clock of 2491 MHz, significantly higher than the A4000 Mobile's 1680 MHz boost clock.

Q: What are the transistor counts and die sizes?

A: The A4000 Mobile uses the GA104 chip with 17,400 million transistors on a 392 mm² die. The RX 6600 uses the Navi 23 chip with 11,060 million transistors on a 237 mm² die. The RX 6600 has a higher transistor density at 46.7M per mm² versus 44.4M per mm² for the A4000 Mobile.

Architecture Differences

The NVIDIA RTX A4000 Mobile is built on the Ampere architecture using the GA104 chip, manufactured by Samsung on an 8 nm process. It is part of the Ampere-MW (Ax000) generation, with a predecessor in Quadro Turing-M and a successor in Ada-MW. Its 17,400 million transistors are packed into a 392 mm² die, giving a transistor density of 44.4M per mm². The architecture includes dedicated RT cores and Tensor cores: 40 RT cores and 160 Tensor cores. This hardware is designed for professional workloads, including ray tracing and AI-accelerated tasks.

The AMD Radeon RX 6600 uses the RDNA 2.0 architecture with the Navi 23 chip, fabricated by TSMC on a 7 nm process. It belongs to the Navi II (RX 6000) generation, with Navi as its predecessor and Navi III as its successor. The chip contains 11,060 million transistors on a 237 mm² die, resulting in a slightly higher transistor density of 46.7M per mm². RDNA 2.0 also includes 28 RT cores, but there are no Tensor cores listed for this GPU. The architecture is optimized for gaming and consumer graphics, with a focus on power efficiency per clock.

The process node difference is notable: the RX 6600 uses TSMC's 7 nm process, while the A4000 Mobile uses Samsung's 8 nm process. Despite the smaller node, the RX 6600 has fewer transistors but a higher density per square millimeter. The A4000 Mobile's larger die and higher transistor count reflect its more complex compute capabilities, including the Tensor core array absent from the RX 6600.

Both GPUs support DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. The A4000 Mobile's display outputs are described as "Portable Device Dependent," reflecting its mobile workstation nature, while the RX 6600 has standard desktop outputs: 1x HDMI 2.1 and 3x DisplayPort 1.4a.

Specification Differences

The two GPUs differ substantially in core configuration. The NVIDIA RTX A4000 Mobile has 5120 shading units, 160 texture mapping units (TMUs), and 80 render output units (ROPs). The AMD Radeon RX 6600 has 1792 shading units, 112 TMUs, and 64 ROPs. The A4000 Mobile also carries 40 RT cores and 160 Tensor cores, while the RX 6600 has 28 RT cores and no Tensor cores.

Clock speeds are another major differentiator. The A4000 Mobile runs at a base clock of 1140 MHz and a boost clock of 1680 MHz. The RX 6600 starts at 1626 MHz base, boosts to 2491 MHz, and has a game clock of 2044 MHz. The RX 6600's memory operates at 1750 MHz (14 Gbps effective), while the A4000 Mobile's memory runs at 1500 MHz (12 Gbps effective). However, the A4000 Mobile's 256-bit memory bus gives it 384.0 GB/s bandwidth, versus the RX 6600's 128-bit bus and 224.0 GB/s bandwidth.

Both have 8 GB of GDDR6 memory. The A4000 Mobile is a mobile part with no power connectors listed, a TDP of 115 W, and no slot width or dimensions specified. The RX 6600 is a desktop dual-slot card measuring 190 mm by 110 mm by 40 mm, with a TDP of 132 W, a single 8-pin power connector, and a suggested PSU of 300 W. The A4000 Mobile uses a PCIe 4.0 x16 interface, while the RX 6600 uses PCIe 4.0 x8.

In terms of raw throughput, the A4000 Mobile delivers 134.4 GPixel/s pixel rate and 268.8 GTexel/s texture rate. The RX 6600 delivers 159.4 GPixel/s and 279.0 GTexel/s, meaning it is faster on both per-pixel and per-texture operations. For FP32 compute, the A4000 Mobile reaches 17.20 TFLOPS, while the RX 6600 reaches 8.928 TFLOPS. For FP16, the A4000 Mobile again hits 17.20 TFLOPS (at a 1:1 ratio), while the RX 6600 hits 17.86 TFLOPS (at a 2:1 ratio). The RX 6600 also carries a launch MSRP of 329 USD.

Head-to-Head Benchmarks

The head-to-head comparison shows 4 wins for the NVIDIA RTX A4000 Mobile and 5 wins for the AMD Radeon RX 6600, but the magnitude of those wins varies dramatically.

The A4000 Mobile's most dominant victory comes in Geekbench OpenCL, where it scores 97178 against the RX 6600's 28850. That is a 236.8% advantage, driven by the NVIDIA card's much higher FP32 throughput and Tensor core support. In Geekbench Vulkan, the A4000 Mobile also wins, scoring 73002 versus 67623, an 8% margin. The NVIDIA card takes Passmark DirectX 12 as well, scoring 66 against 51, a 29.4% lead. It also wins Passmark DirectX 10 with 105 versus 95, a 10.5% difference.

The RX 6600 counters in several tests. In Passmark DirectX 11, it scores 152 versus 127, a 16.4% advantage. In Passmark DirectX 9, it scores 197 versus 157, a 20.3% lead. The RX 6600's biggest win is in Passmark G2D, where it scores 889 versus 585, a 34.2% advantage. It also narrowly wins Passmark G3D, 15096 versus 14796, a 2% margin, and Passmark GPU Compute, 6554 versus 6394, a 2.4% margin.

The pattern is clear: the A4000 Mobile dominates in compute-oriented workloads like OpenCL and Vulkan, while the RX 6600 excels in legacy DirectX APIs and 2D graphics operations. The RX 6600's higher clock speeds and larger pixel rate contribute to its wins in DirectX 9 and 11. The A4000 Mobile's greater shading unit count and memory bandwidth drive its compute performance. In the overall average benchmark score, the A4000 Mobile leads with 21379 versus 19036, and it holds a 66th percentile rank versus 63rd for the RX 6600.