AMD Radeon RX 6600M vs NVIDIA RTX A4000 Comparison

FAQ

Q: Which GPU is faster in the 3DMark Steel Nomad DX12 test?

A: The NVIDIA RTX A4000 scores 2604, while the AMD Radeon RX 6600M scores 1495. That is a 74.2% advantage for the RTX A4000.

Q: How do the two cards compare in compute workloads?

A: In Geekbench OpenCL, the RTX A4000 scores 105739 versus 67765 for the RX 6600M, a 56% lead. In Passmark GPU Compute, the lead is 72.9%, with scores of 9760 and 5646 respectively.

Q: What is the memory configuration difference?

A: The RTX A4000 has 16 GB of GDDR6 on a 256-bit bus with 448.0 GB/s bandwidth. The RX 6600M has 8 GB of GDDR6 on a 128-bit bus with 224.0 GB/s bandwidth.

Q: Are these cards still in production?

A: No, both are listed as end-of-life in the database. The RTX A4000 released on 2021-04-11, and the RX 6600M released on 2021-05-30.

Q: Which card has better DirectX 12 performance?

A: The RTX A4000 scores 72 in Passmark DirectX 12, while the RX 6600M scores 52, a 38.5% difference. Both support DirectX 12 Ultimate (12_2).

Q: How do their overall benchmark averages compare?

A: The RTX A4000 has an average benchmark score of 26683 and sits at the 72nd percentile of all GPUs. The RX 6600M averages 23273 and sits at the 68th percentile.

Architecture Differences

The RTX A4000 is built on NVIDIA's Ampere architecture, using the GA104 chip fabricated by Samsung on an 8 nm process. The die measures 392 mm² and contains 17,400 million transistors, giving a transistor density of 44.4 million per mm². It is part of the Workstation Ampere (Ax000) generation, with the Quadro Turing as its predecessor and Workstation Ada as its successor.

The RX 6600M uses AMD's RDNA 2.0 architecture, built on the Navi 23 chip manufactured by TSMC on a 7 nm process. The die is significantly smaller at 237 mm², with 11,060 million transistors and a higher transistor density of 46.7 million per mm². It belongs to the Navi Mobile (RX 6000M) generation, succeeding Polaris Mobile.

Core configuration differs substantially. The RTX A4000 carries 6144 shading units, 192 texture mapping units, 96 ROPs, 48 ray tracing cores, and 192 tensor cores. The RX 6600M has 1792 shading units, 112 TMUs, 64 ROPs, and 28 ray tracing cores, with no tensor cores listed. This is a fundamental architectural split: NVIDIA pairs its ray tracing hardware with dedicated tensor cores for AI-accelerated workloads, while AMD relies on a leaner shader arrangement.

Clock behavior also reflects their different design intents. The RTX A4000 runs a base clock of 735 MHz and boosts to 1560 MHz, a conservative range for a workstation card. The RX 6600M runs much higher, with a base of 2068 MHz, a boost of 2416 MHz, and a game clock of 2177 MHz. Despite the higher clocks, the RX 6600M delivers lower raw throughput because it has far fewer execution units.

Both cards support DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. The RTX A4000 uses a PCIe 4.0 x16 interface, while the RX 6600M uses PCIe 4.0 x8. Memory clocks are identical at 1750 MHz with 14 Gbps effective, but the bus width difference changes the actual bandwidth story.

Head-to-Head Benchmarks

The RTX A4000 wins all ten recorded head-to-head benchmarks. The database shows no test where the RX 6600M takes the lead. The margin varies widely by workload, which tells a useful story about where each card's strengths lie.

The biggest gap appears in 3DMark Steel Nomad DX12, where the RTX A4000 scores 2604 versus 1495, a 74.2% advantage. This is a modern DirectX 12 workload that stresses the full graphics pipeline, and the workstation card's larger core count and wider memory bus show clearly. The Geekbench Vulkan result is nearly as lopsided: 127645 versus 73740, a 73.1% lead. Vulkan's low-level access to hardware tends to reward raw resource availability, and the RTX A4000 has more of everything.

Compute performance follows a similar pattern. Passmark GPU Compute shows 9760 versus 5646, a 72.9% difference. Geekbench OpenCL shows 105739 versus 67765, a 56% lead. These results reflect the RTX A4000's 19.17 TFLOPS FP32 throughput against the RX 6600M's 8.659 TFLOPS, a more than 2:1 ratio. The RTX A4000 also lists 192 tensor cores, which can accelerate certain compute paths, though the database does not isolate tensor workloads.

Older DirectX benchmarks show smaller but still decisive margins. Passmark DirectX 10 scores 126 versus 87, a 44.8% lead. Passmark DirectX 12 scores 72 versus 52, a 38.5% lead. Passmark DirectX 9 scores 240 versus 184, a 30.4% lead. Passmark DirectX 11 is the closest result of the set, with 158 versus 136, a 16.2% margin. This narrower gap in DirectX 11 suggests that the RX 6600M's high clocks help close the distance in lighter legacy workloads, but they cannot overcome the fundamental resource deficit.

The 2D and general 3D tests follow the same direction. Passmark G2D shows 1024 versus 728, a 40.7% lead for the RTX A4000. Passmark G3D shows 19459 versus 13929, a 39.7% lead. The consistency across every category, from 2D rasterization to modern 3D to compute, indicates that this is not a workload-specific quirk but a broad performance gap.

The RTX A4000 also holds a higher position in the overall GPU percentile ranking, sitting at the 72nd percentile versus the RX 6600M's 68th. Its average benchmark score of 26683 compares to 23273 for the RX 6600M, a difference of roughly 14.7%.

Specification Differences

The two cards differ on nearly every core specification. The RTX A4000 uses the GA104 chip on an 8 nm Samsung process, while the RX 6600M uses Navi 23 on a 7 nm TSMC process. Transistor counts are 17,400 million versus 11,060 million, and die sizes are 392 mm² versus 237 mm².

Shading units favor the RTX A4000 heavily: 6144 versus 1792. TMUs are 192 versus 112, and ROPs are 96 versus 64. Ray tracing cores are 48 versus 28. The RTX A4000 has 192 tensor cores; the RX 6600M has none listed.

Clock speeds favor the RX 6600M. Its base clock of 2068 MHz is nearly three times the RTX A4000's 735 MHz. Boost clocks are 2416 MHz versus 1560 MHz, and the RX 6600M adds a game clock of 2177 MHz that the RTX A4000 does not list.

Memory favors the RTX A4000 in every dimension: 16 GB versus 8 GB, 256-bit versus 128-bit bus, and 448.0 GB/s versus 224.0 GB/s bandwidth. Both use GDDR6 at 1750 MHz with 14 Gbps effective.

Power and physical design differ sharply. The RTX A4000 has a 140 W TDP, uses a single-slot cooler, requires one 6-pin power connector, and lists a 300 W suggested PSU. It measures 241 mm long and 112 mm tall. The RX 6600M is an IGP with a 100 W TDP, no power connectors, no listed dimensions, and no suggested PSU. Its display outputs are described as portable device dependent, while the RTX A4000 has 4x DisplayPort 1.4a.

Throughput rates reflect the core count difference. The RTX A4000 delivers 19.17 TFLOPS FP32 and 19.17 TFLOPS FP16 at a 1:1 ratio. The RX 6600M delivers 8.659 TFLOPS FP32 and 17.32 TFLOPS FP16 at a 2:1 ratio. Pixel rate is close: 149.8 GPixel/s versus 154.6 GPixel/s, with the RX 6600M actually slightly ahead. Texture rate is 299.5 GTexel/s versus 270.6 GTexel/s, favoring the RTX A4000.

Where Each One Wins

The RTX A4000 wins in every recorded benchmark, so the practical question is where its advantages matter most. The largest margins appear in modern graphics and compute workloads. The 74.2% lead in 3DMark Steel Nomad DX12 and the 73.1% lead in Geekbench Vulkan indicate that demanding DirectX 12 and Vulkan titles will run substantially better on the RTX A4000. The 72.9% lead in Passmark GPU Compute makes it the clear choice for GPU-accelerated compute tasks, and its 192 tensor cores add capability for AI workflows that the RX 6600M cannot match at all.

The RX 6600M has no benchmark wins to claim, but its profile suggests specific strengths. Its higher clocks and the 2:1 FP16 ratio mean it can process half-precision workloads at up to 17.32 TFLOPS, which is close to the RTX A4000's 19.17 TFLOPS. Its pixel rate of 154.6 GPixel/s is slightly higher than the RTX A4000's 149.8 GPixel/s, indicating that fill-rate-limited scenarios are not as one-sided. The 100 W TDP and IGP form factor make it suitable for portable systems where power and space are constrained, though the database does not provide performance-per-watt figures.

The legacy DirectX results give the RX 6600M its best relative showing. The 16.2% gap in Passmark DirectX 11 is the smallest of any test, suggesting that older titles with lighter demands narrow the distance. Still, even there, the RTX A4000 comes out ahead.

The Verdict

The data is unambiguous: the NVIDIA RTX A4000 is the faster card in every single recorded test. It wins all ten head-to-head benchmarks, holds a higher percentile ranking at 72 versus 68, and has a higher average benchmark score of 26683 versus 23273. For anyone building a workstation where performance is the priority, the RTX A4000 is the choice. Its 16 GB memory capacity, 448.0 GB/s bandwidth, and 19.17 TFLOPS FP32 throughput give it a commanding lead in graphics and compute alike.

The AMD Radeon RX 6600M is not without a case. Its 100 W TDP, IGP form factor, and portable device dependent outputs point to laptop and compact system integration. The higher clocks and competitive FP16 throughput make it a reasonable choice for half-precision compute in constrained environments. The pixel rate advantage is marginal but real. However, the benchmark results do not give it a single winning category, and the 74.2% gap in modern DirectX 12 is too large to ignore.

The practical advice from the database is straightforward: choose the RTX A4000 for desktop workstation tasks that demand maximum graphics and compute throughput. Choose the RX 6600M only when the system form factor requires an integrated mobile solution and the performance gap is acceptable. Both cards are end-of-life, so availability is a separate consideration outside the recorded data.