AMD Radeon RX 6600M vs NVIDIA GeForce RTX 3090 Comparison

Head-to-Head Benchmarks

The benchmark data presents a lopsided contest. The NVIDIA GeForce RTX 3090 wins 9 out of 10 recorded head-to-head tests, with the AMD Radeon RX 6600M taking a single victory. The magnitude of these wins, however, tells a more nuanced story about where each card operates.

The most decisive result for the RTX 3090 comes in 3DMark Steel Nomad DX12, where it scores 5,118 points against the RX 6600M's 1,495 points. That is a 242.3% advantage, the largest delta in the entire comparison. This gap reflects the vast difference in raw throughput and sustained rendering capability under modern API load.

Geekbench OpenCL similarly shows a wide margin. The RTX 3090 records 172,758 points versus 67,765 points for the RX 6600M, a 154.9% advantage. Compute workloads follow the same pattern: Passmark GPU Compute shows 15,356 versus 5,646, a 172% lead for the NVIDIA part.

The RTX 3090 also dominates the older legacy DirectX tests. In Passmark DirectX 10, it scores 182 versus 87 (109.2% ahead). DirectX 11 shows 220 versus 136 (61.8% ahead). DirectX 9 is the narrowest of these, 268 versus 184 (45.7% ahead). Even the 2D test, Passmark G2D, goes to the NVIDIA at 1,063 versus 728, a 46% lead.

The single AMD win is in Geekbench Vulkan. Here the RX 6600M scores 73,740 against the RTX 3090's 53,927. That is a 26.9% advantage for the AMD. This is an interesting outlier. In a test that stresses different API pathways, the RDNA 2.0 architecture in the mobile part is able to flip the script.

Passmark G3D follows the expected trend, with the RTX 3090 scoring 26,645 versus 13,929, a 91.3% advantage. The overall average benchmark scores reflect this: the RTX 3090 sits at 27,565 average, while the RX 6600M sits at 23,273. The percentile rankings also differ, with the RTX 3090 in the 73rd percentile of all GPUs, and the RX 6600M in the 68th.

Architecture Differences

The underlying designs could not be more different. The RTX 3090 uses the GA102 chip built on Ampere architecture, manufactured on Samsung's 8 nm process. The die is enormous at 628 mm², housing 28,300 million transistors. The RX 6600M uses the Navi 23 chip on RDNA 2.0, built on TSMC's 7 nm process. Its die is smaller at 237 mm², with 11,060 million transistors. The transistor density is remarkably close (45.1M per mm² for the NVIDIA, 46.7M per mm² for the AMD), showing the process advantage of the 7 nm node for the smaller chip.

The execution resources differ by a factor of roughly six. The RTX 3090 has 10,496 shading units, 328 texture units, 112 ROPs, and 82 RT cores. The RX 6600M has 1,792 shading units, 112 texture units, 64 ROPs, and 28 RT cores. The NVIDIA also includes 328 tensor cores, while the AMD has none listed.

Clock speeds tell the opposite story. The RX 6600M has a base clock of 2,068 MHz and a boost clock of 2,416 MHz. The RTX 3090 has a base clock of 1,395 MHz and a boost clock of 1,695 MHz. The AMD part runs at a much higher frequency, which helps it close some of the gap in specific workloads, but the massive difference in resource count still dominates.

Memory architecture is also fundamentally different. The RTX 3090 uses 24 GB of GDDR6X on a 384-bit bus, delivering 936.2 GB/s of bandwidth. The RX 6600M uses 8 GB of GDDR6 on a 128-bit bus, delivering 224.0 GB/s. The NVIDIA card has over four times the memory bandwidth. The memory clock for the RTX is listed at 1,219 MHz (19.5 Gbps effective), while the AMD runs at 1,750 MHz (14 Gbps effective). The AMD's higher physical memory clock is offset by the narrower bus.

The FP32 compute figures quantify the raw difference. The RTX 3090 delivers 35.58 TFLOPS, while the RX 6600M delivers 8.659 TFLOPS. For FP16, the NVIDIA does 35.58 TFLOPS at a 1:1 ratio, while the AMD does 17.32 TFLOPS at a 2:1 ratio, meaning the AMD can double its FP16 rate when it uses packed math.

Where Each One Wins

The RTX 3090 is the clear leader for almost every metric that the database records. The 3DMark Steel Nomad result at 242.3% ahead makes it the obvious choice for high-end DX12 gaming. For compute work, the 172% lead in Passmark GPU compute and the 154.9% lead in OpenCL show that heavy number crunching is firmly in NVIDIA territory. The 91.3% lead in Passmark G3D reinforces this point for general 3D rendering.

The RX 6600M's single win in Geekbench Vulkan is notable. A 26.9% advantage in Vulkan suggests that the RDNA 2.0 architecture has a particular strength in that API's command processing and asynchronous compute paths. For developers targeting Vulkan specifically, this mobile GPU may punch above its weight class. It also has a lower power profile, with a 100 W TDP, which is a significant consideration for portable systems, though the data does not specify a frame-rate-per-watt comparison.

The RTX 3090 also wins in the 2D Passmark test, which is often linked to memory and ROP efficiency. Its 46% lead there is smaller than the 3D gaps, but still decisive.

Specification Differences

| Specification | NVIDIA GeForce RTX 3090 | AMD Radeon RX 6600M |

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

| Process Node | 8 nm (Samsung) | 7 nm (TSMC) |

| Transistors | 28,300 million | 11,060 million |

| Die Size | 628 mm² | 237 mm² |

| Base Clock | 1,395 MHz | 2,068 MHz |

| Boost Clock | 1,695 MHz | 2,416 MHz |

| Memory Size | 24 GB | 8 GB |

| Memory Type | GDDR6X | GDDR6 |

| Memory Bus | 384 bit | 128 bit |

| Memory Bandwidth | 936.2 GB/s | 224.0 GB/s |

| Shading Units | 10,496 | 1,792 |

| TMUs | 328 | 112 |

| ROPs | 112 | 64 |

| RT Cores | 82 | 28 |

| Tensor Cores | 328 | None |

| Pixel Rate | 189.8 GPixel/s | 154.6 GPixel/s |

| Texture Rate | 556.0 GTexel/s | 270.6 GTexel/s |

| FP32 | 35.58 TFLOPS | 8.659 TFLOPS |

| FP16 | 35.58 TFLOPS (1:1) | 17.32 TFLOPS (2:1) |

| TDP | 350 W | 100 W |

| Bus Interface | PCIe 4.0 x16 | PCIe 4.0 x8 |

| Display Outputs | 1x HDMI 2.1, 3x DisplayPort 1.4a | Portable Device Dependent |

| Slot Width | Triple-slot | IGP |

| Power Connectors | 1x 12-pin | None |

| Release Date | 2020-08-31 | 2021-05-30 |

The two cards have identical DirectX 12 Ultimate (12_2) support and OpenGL 4.6, and both list Vulkan 1.4. The RTX 3090 is a triple-slot card with a 1x 12-pin power connector and a 750 W suggested PSU. The RX 6600M is an IGP (integrated graphics processor) part with no power connectors and no suggested PSU listed. The RTX 3090 is 336 mm long, 140 mm tall, and 61 mm wide. The RX 6600M has no listed dimensions, as it is designed for portable devices.

FAQ

Q: Which GPU has more raw compute power in FP32?

A: The RTX 3090 has 35.58 TFLOPS FP32 performance, which is over four times the 8.659 TFLOPS of the RX 6600M.

Q: Does the RX 6600M win any benchmark against the RTX 3090?

A: Yes, the RX 6600M wins the Geekbench Vulkan test with a score of 73,740, which is 26.9% higher than the RTX 3090's 53,927.

Q: How much faster is the RTX 3090 in the 3DMark Steel Nomad test?

A: The RTX 3090 scores 5,118 points to 1,495 points for the RX 6600M, a 242.3% advantage.

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

A: The RTX 3090 has 936.2 GB/s, while the RX 6600M has 224.0 GB/s. The NVIDIA part has over four times the bandwidth.

Q: Are there any architectural similarities?

A: Both support DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. They also both support ray tracing via RT cores, though the RTX 3090 has 82 RT cores compared to 28 on the RX 6600M.

Q: Which GPU has a smaller die and process node?

A: The RX 6600M uses TSMC's 7 nm node and has a 237 mm² die. The RTX 3090 uses Samsung's 8 nm node and has a 628 mm² die. The AMD is smaller and denser, with 46.7 million transistors per mm² vs 45.1 million per mm² for the NVIDIA.