AMD Radeon RX 6600 XT vs NVIDIA RTX A4000 Mobile Comparison

The Verdict

The recorded data splits this comparison cleanly along workload type. The AMD Radeon RX 6600 XT wins 6 of 9 head-to-head benchmark tests, while the NVIDIA RTX A4000 Mobile wins 3. The AMD card’s average benchmark score of 24442 places it at the 70th percentile of all GPUs, versus the NVIDIA mobile part’s 21379 average and 66th percentile. If the priority is raw rasterization and legacy API performance, the RX 6600 XT is the stronger pick. If the workload leans on OpenCL compute or the Vulkan API, the RTX A4000 Mobile takes the lead. The RTX A4000 Mobile’s nearest rivals include the AMD Radeon HD 8970M (0.7% behind) and the AMD Radeon RX Vega M GL (1.1% behind), which shows it sits in a lower performance tier than the RX 6600 XT, whose nearest rivals include the NVIDIA GeForce RTX 2080 SUPER (1.1% behind) and the Intel Arc A350M (0.8% ahead). The RX 6600 XT is end-of-life and carries a launch MSRP of 379 USD, while the RTX A4000 Mobile is also end-of-life with no recorded launch MSRP.

Architecture Differences

The two GPUs come from different design philosophies. The AMD Radeon RX 6600 XT uses the Navi 23 chip built on RDNA 2.0 architecture, produced on a 7 nm process at TSMC. The RTX A4000 Mobile uses the GA104 chip with Ampere architecture, produced on an 8 nm process at Samsung. The AMD chip integrates 11,060 million transistors on a 237 mm² die, giving a transistor density of 46.7M per mm². The NVIDIA chip packs 17,400 million transistors on a 392 mm² die, with a lower density of 44.4M per mm². The larger die and transistor count for NVIDIA do not translate into a higher average score in the database.

Clock behavior differs significantly. The RX 6600 XT has a base clock of 1968 MHz, a boost clock of 2589 MHz, and a game clock of 2359 MHz. The RTX A4000 Mobile runs at a base of 1140 MHz and a boost of 1680 MHz, with no game clock listed. Memory configurations also diverge: both have 8 GB GDDR6, but the AMD uses a 128-bit bus with 256.0 GB/s bandwidth, while the NVIDIA uses a 256-bit bus with 384.0 GB/s bandwidth. The AMD memory clock is listed as 2000 MHz with 16 Gbps effective, while NVIDIA’s is 1500 MHz with 12 Gbps effective.

Compute resource allocation is heavily asymmetric. The RX 6600 XT has 2048 shading units, 128 TMUs, and 64 ROPs. The RTX A4000 Mobile has 5120 shading units, 160 TMUs, and 80 ROPs. Ray tracing cores are 32 versus 40 in favor of NVIDIA. The RTX A4000 Mobile also includes 160 tensor cores, which the RX 6600 XT lacks entirely. Pixel rate favors AMD at 165.7 GPixel/s versus NVIDIA’s 134.4 GPixel/s. Texture rate also favors AMD at 331.4 GTexel/s versus 268.8 GTexel/s. FP32 compute is higher on NVIDIA at 17.20 TFLOPS versus AMD’s 10.60 TFLOPS. FP16 shows a stark difference: AMD lists 21.21 TFLOPS with a 2:1 ratio, while NVIDIA lists 17.20 TFLOPS with a 1:1 ratio.

Power and physical design diverge. The RX 6600 XT has a TDP of 160 W, is dual-slot, requires a single 8-pin power connector, and suggests a 450 W power supply. The RTX A4000 Mobile has a TDP of 115 W, lists no slot width, no power connectors, and no suggested PSU. The AMD card is 190 mm long, 110 mm high, and 40 mm wide, while NVIDIA lists no dimensions. Bus interface differs: PCIe 4.0 x8 for AMD, PCIe 4.0 x16 for NVIDIA. Display outputs are 1x HDMI 2.1 and 3x DisplayPort 1.4a for AMD, while NVIDIA’s are listed as portable device dependent.

Where Each One Wins

The RX 6600 XT dominates in legacy DirectX tests and general graphics workloads. In PassMark DirectX 11, it scores 163 versus 127, a 28.3% advantage. In DirectX 9, it scores 194 versus 157, a 23.6% lead. The PassMark G3D score of 16461 versus 14796 shows an 11.3% advantage. The G2D score is 912 versus 585, a 55.9% gap. GPU compute also favors AMD: 7520 versus 6394, a 17.6% margin. Even in DirectX 10, AMD wins narrowly: 109 versus 105, a 3.8% edge.

The RTX A4000 Mobile wins in OpenCL and Vulkan, which are more modern compute-oriented APIs. In Geekbench OpenCL, it scores 97178 versus 80503, a 17.2% advantage. In Geekbench Vulkan, it wins 73002 versus 72417, but only by 0.8%. The sole DirectX 12 test in the head-to-head also goes to NVIDIA: PassMark DirectX 12 scores 66 versus 61, a 7.6% lead. This suggests the NVIDIA architecture handles the latest DirectX feature level better, even though AMD wins the older APIs.

The overall win count reflects this split: AMD takes 6 wins, NVIDIA takes 3. The average benchmark score reinforces AMD’s edge: 24442 versus 21379, a difference of roughly 14.3%. The percentile ranking also supports AMD, with 70 versus 66. For users prioritizing legacy game compatibility, 2D desktop performance, or OpenGL-era workloads, the RX 6600 XT is clearly ahead. For compute-heavy tasks that leverage OpenCL, or for Vulkan-based engines, the RTX A4000 Mobile is the better choice.

FAQ

Q: Which GPU has the higher average benchmark score?

A: The AMD Radeon RX 6600 XT has an average benchmark score of 24442, while the NVIDIA RTX A4000 Mobile scores 21379. The AMD card also ranks higher at the 70th percentile of all GPUs versus NVIDIA’s 66th percentile.

Q: How do the two compare in DirectX 11 performance?

A: The RX 6600 XT scores 163 in PassMark DirectX 11, which is 28.3% higher than the RTX A4000 Mobile’s 127. This is the largest single-test margin in the head-to-head for AMD.

Q: Where does the RTX A4000 Mobile have a clear advantage?

A: The NVIDIA part wins Geekbench OpenCL with a score of 97178 versus 80503, a 17.2% lead. It also wins Geekbench Vulkan (73002 versus 72417) and PassMark DirectX 12 (66 versus 61).

Q: What is the memory bandwidth difference?

A: The RTX A4000 Mobile has 384.0 GB/s bandwidth on a 256-bit bus, while the RX 6600 XT has 256.0 GB/s on a 128-bit bus. Despite this, AMD wins most graphics tests.

Q: Which GPU has more shading units?

A: The RTX A4000 Mobile has 5120 shading units, while the RX 6600 XT has 2048. The NVIDIA part also has more TMUs (160 versus 128), ROPs (80 versus 64), and ray tracing cores (40 versus 32).

Q: How do the transistor counts compare?

A: The RTX A4000 Mobile has 17,400 million transistors on a 392 mm² die, while the RX 6600 XT has 11,060 million on a 237 mm² die. The AMD chip has a higher transistor density at 46.7M per mm² versus NVIDIA’s 44.4M per mm².

Head-to-Head Benchmarks

The largest win for AMD comes in PassMark G2D, where the RX 6600 XT scores 912 versus 585, a 55.9% advantage. This test measures 2D graphics operations, and the gap is substantial. The DirectX 11 test shows a 28.3% margin (163 versus 127), and DirectX 9 shows a 23.6% margin (194 versus 157). GPU compute favors AMD by 17.6% (7520 versus 6394). The G3D score, which is a broader graphics performance indicator, gives AMD an 11.3% lead (16461 versus 14796). Even the DirectX 10 test, though close, goes to AMD at 109 versus 105 (3.8%).

For NVIDIA, the biggest win is in Geekbench OpenCL: 97178 versus 80503, a 17.2% margin. This is a compute-oriented benchmark that stresses general-purpose GPU processing. The Vulkan test is much closer, with NVIDIA ahead by only 0.8% (73002 versus 72417). The PassMark DirectX 12 test gives NVIDIA a 7.6% edge (66 versus 61). These three wins show that NVIDIA’s architecture is competitive in modern API environments, but the magnitude of the OpenCL win is the only one that approaches AMD’s larger margins.

The pattern is consistent: AMD wins the older DirectX versions and 2D/3D raster workloads, while NVIDIA wins the compute and Vulkan tests. The average score difference of 3063 points (24442 versus 21379) is driven by AMD’s strong showing in the PassMark suite, which carries more weight in the aggregate. The RTX A4000 Mobile’s higher FP32 compute (17.20 TFLOPS versus 10.60 TFLOPS) does not translate into a win in PassMark GPU Compute, where AMD leads by 17.6%. This suggests that raw FLOPs are not the sole determinant of real-world compute performance in these tests. Similarly, NVIDIA’s higher memory bandwidth (384.0 GB/s versus 256.0 GB/s) does not help in most graphics tests, indicating that the RX 6600 XT’s higher clock speeds (boost 2589 MHz versus 1680 MHz) and RDNA 2.0 efficiency compensate for the narrower bus. The data shows a clear trade-off: NVIDIA’s larger chip and compute resources matter in OpenCL, but AMD’s higher clocks and older API optimization win the majority of tests.