AMD Radeon RX 6600M vs AMD Radeon RX 7900 XTX Comparison

Head-to-Head Benchmarks

The head-to-head data presents a stark contrast between these two Radeon parts. The AMD Radeon RX 7900 XTX dominates in nine of the ten recorded tests, while the AMD Radeon RX 6600M takes a single, notable victory. The sheer scale of the performance gap in most tests is far larger than the one-win swing suggests.

The RX 7900 XTX's strongest showing comes in the modern API tests. In 3DMark Steel Nomad (DX12), it scores 6841 against the RX 6600M's 1495, a delta of -78.1% from the perspective of the mobile part. This is the single largest performance gap recorded in the comparison. The desktop card also leads decisively in the Passmark legacy and modern API suite. It posts a score of 356 in DirectX 11 versus 136, a 61.8% advantage. In DirectX 12, the 7900 XTX scores 131 compared to 52, a 60.3% lead. The pattern holds in DirectX 10 (166 vs. 87) and DirectX 9 (330 vs. 184), where the desktop part leads by 47.6% and 44.2%, respectively.

The 7900 XTX also excels in compute-heavy workloads. The Passmark G3D score of 31,238 is 55.4% higher than the RX 6600M's 13,929. The Passmark GPU Compute score shows an even larger delta: 17,689 versus 5,646, which translates to a 68.1% advantage for the 7900 XTX. The 2D performance test also favors the desktop card, with a score of 1267 against 728, a 42.5% lead.

The RX 6600M's sole victory comes in the Geekbench OpenCL test. Here, the mobile GPU scores 67,765, while the RX 7900 XTX records 50,465. This is a 34.3% advantage for the RX 6600M. This single data point is an outlier and does not align with the results of other compute-focused tests in the database. Meanwhile, in the Geekbench Vulkan test, the 7900 XTT regains control, scoring 85,612 versus 73,740, a 13.9% lead.

The average benchmark scores in the database reflect this mixed picture. The RX 6600M has an average benchmark score of 23,273, which places it at the 68th percentile of all GPUs. The RX 7900 XTX has an average score of 19,410, which puts it at the 64th percentile. This is a critical observation: the RX 7900 XTX's average is dragged down by its relatively low scores in the Geekbench OpenCL test, while the RX 6600M's average is buoyed by its high score there. The RX 7900 XTX's nearest rivals based on average score include the NVIDIA GeForce GTX 1060 3 GB (delta of 0.4%) and the AMD FirePro D300 (delta of -1.2%). The RX 6600M's rivals are clustered closer, with the AMD Radeon R9 M290X being essentially a tie (delta of 0%) and the AMD Radeon Pro Vega 16 just 0.1% behind.

Architecture Differences

The two GPUs come from different generations and are built on different process nodes. The RX 6600M is based on the Navi 23 chip, which uses the RDNA 2.0 architecture and is fabricated on TSMC's 7 nm node. The RX 7900 XTX is based on the Navi 31 chip, which uses the RDNA 3.0 architecture and is fabricated on TSMC's 5nm node. This node shrink is likely a major factor in the 7900 XTX's higher transistor density: 109.1 million transistors per square millimeter versus 46.7 million for the 6600M.

The die sizes reflect their different purposes. The RX 6600M has a die size of 237 square millimeters and contains 11,060 million transistors. The RX 7900 XTX has a significantly larger die of 529 square millimeters and contains 57,700 million transistors. The desktop card has more than five times the transistor count of the mobile part.

The compute resources are also vastly different. The RX 6600M has 1,792 shading units, 112 texture mapping units (TMUs), and 64 render output units (ROPs). The RX 7900 XTX has 6,144 shading units, 384 TMUs, and 192 ROPs. The desktop card has 3.4 times the shading units, 3.4 times the TMUs, and 3 times the ROPs. The ray tracing hardware follows the same pattern, with the RX 7900 XTX having 96 RT cores compared to the RX 6600M's 28.

Memory capacity and bandwidth are key differentiators. The RX 6600M comes with 8 GB of GDDR6 memory on a 128-bit bus, providing 224.0 GB/s of bandwidth. The RX 7900 XTX ships with 24 GB of GDDR6 memory on a 384-bit bus, providing 960.0 GB/s of bandwidth. This is a 4.3x difference in bandwidth and a 3x difference in capacity.

The clock speeds are closer than the other specifications. The RX 6600M has a base clock of 2068 MHz, a boost clock of 2416 MHz, and a game clock of 2177 MHz. The RX 7900 XTX has a slightly lower base clock of 1929 MHz, but a higher boost clock of 2498 MHz and a higher game clock of 2365 MHz. The memory clocks are also notable: the RX 6600M operates at 1750 MHz (14 Gbps effective), while the RX 7900 XTX operates at 2500 MHz (20 Gbps effective).

The power profiles are entirely different. The RX 6600M is a mobile part with a TDP of 100 W and no power connectors, as it is an IGP (Integrated Graphics Processor). The RX 7900 XTX is a desktop part with a TDP of 355 W, requiring 2x 8-pin power connectors and a suggested power supply of 750 W. The RX 6600M is a single-slot IGP, while the RX 7900 XTX is a dual-slot card with dimensions of 287 mm in length, 110 mm in height, and 51 mm in width.

Where Each One Wins

The data presents a clean division of labor. The RX 7900 XTX is the clear winner in almost every computationally demanding scenario. Its massive leads in the 3DMark Steel Nomad test and the Passmark G3D test indicate that it is far superior for traditional gaming workloads, particularly at high resolutions and with modern APIs. The 61.8% lead in DirectX 11 and 60.3% lead in DirectX 12 reinforce this point. The 68.1% advantage in Passmark GPU Compute also shows that professional and content creation tasks, such as rendering and machine learning, would heavily favor the desktop card.

The RX 6600M's only win in Geekbench OpenCL is a significant one. The 34.3% lead over the RX 7900 XTX in this specific test is a notable anomaly. The database shows that this is the only OpenCL test listed, and it may not be representative of typical OpenCL performance. The RX 6600M's lower power consumption (100 W TDP) and its mobile form factor are its primary strengths, but the benchmark data does not show a clear performance win beyond that single test. The RX 7900 XTX has a 13.9% lead in the Geekbench Vulkan test, a further sign that the desktop card is superior for real-time graphics APIs.

The percentile rankings provide additional context. The RX 6600M sits at the 68th percentile for all GPUs, while the RX 7900 XTX sits at the 64th. This means the RX 6600M, despite being a mobile part, is ranked higher than the RX 7900 XTX in the database's overall distribution. This is due to the RX 6600M's high average score, which is boosted by its exceptional Geekbench OpenCL result.

The Verdict

Based strictly on the recorded data, the AMD Radeon RX 7900 XTX is the dominant performer in the vast majority of tests. It wins nine out of ten head-to-head benchmarks, with margins ranging from 13.9% to 78.1%. The RX 7900 XTX is the clear choice for any workload that relies on DirectX 10, 11, or 12, Vulkan, or general GPU compute. Its 3DMark Steel Nomad score of 6841 is more than 4.5 times that of the RX 6600M, and its Passmark G3D score is more than double.

The AMD Radeon RX 6600M is not a viable alternative in these same tests. Its only victory is in the Geekbench OpenCL test, where it scores 67,765 versus the 7900 XTX's 50,465. This single data point is enough to give it a higher average benchmark score and percentile rank, but it is not enough to recommend it over the RX 7900 XTX for general graphics work. The RX 6600M's primary advantage is its low power consumption and its mobile form factor, but the recorded data shows that this comes at a massive cost to performance. The RX 7900 XTX is the clear winner for anyone who prioritizes performance, while the RX 6600M is only preferable in the specific scenario where its OpenCL performance is the primary requirement.

FAQ

Q: Which GPU has the higher average benchmark score?

A: The AMD Radeon RX 6600M has a higher average benchmark score of 23,273, compared to the RX 7900 XTX's 19,410.

Q: What is the largest performance difference between the two cards?

A: The largest difference is in the 3DMark Steel Nomad DX12 test, where the RX 7900 XTX scores 6841 and the RX 6600M scores 1495, a delta of -78.1% for the RX 6600M.

Q: Does the RX 6600M win any benchmark that measures compute performance?

A: The RX 6600M wins the Geekbench OpenCL test with a score of 67,765, which is 34.3% higher than the RX 7900 XTX's score of 50,465.

Q: How much more bandwidth does the RX 7900 XTX have?

A: The RX 7900 XTX has a memory bandwidth of 960.0 GB/s, while the RX 6600M has 224.0 GB/s.

Q: What is the difference in TDP between the two cards?

A: The RX 6600M has a TDP of 100 W, while the RX 7900 XTX has a TDP of 355 W.

Q: What is the difference in their percentile rankings?

A: The RX 6600M ranks in the 68th percentile of all GPUs, while the RX 7900 XTX ranks in the 64th percentile.

Specification Differences

Here is a direct comparison of the fields where the two GPUs differ:

| Specification | AMD Radeon RX 6600M | AMD Radeon RX 7900 XTX |

| :--- | :--- | :--- |

| Architecture | RDNA 2.0 | RDNA 3.0 |

| Process Node | 7 nm | 5 nm |

| Transistors | 11,060 million | 57,700 million |

| Die Size | 237 mm² | 529 mm² |

| Transistor Density | 46.7M / mm² | 109.1M / mm² |

| Base Clock | 2068 MHz | 1929 MHz |

| Boost Clock | 2416 MHz | 2498 MHz |

| Game Clock | 2177 MHz | 2365 MHz |

| Memory Speed | 14 Gbps effective | 20 Gbps effective |

| Memory Size | 8 GB | 24 GB |

| Memory Bus Width | 128 bit | 384 bit |

| Memory Bandwidth | 224.0 GB/s | 960.0 GB/s |

| Shading Units | 1792 | 6144 |

| TMUs | 112 | 384 |

| ROPs | 64 | 192 |

| RT Cores | 28 | 96 |

| Pixel Rate | 154.6 GPixel/s | 479.6 GPixel/s |

| Texture Rate | 270.6 GTexel/s | 959.2 GTexel/s |

| FP32 Performance | 8.659 TFLOPS | 61.39 TFLOPS |

| FP16 Performance | 17.32 TFLOPS (2:1) | 122.8 TFLOPS (2:1) |

| TDP | 100 W | 355 W |

| Slot Width | IGP | Dual-slot |

| Power Connectors | None | 2x 8-pin |

| Suggested PSU | (Not specified) | 750 W |

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

| Display Outputs | Portable Device Dependent | 1x HDMI 2.1, 2x DisplayPort 2.1, 1x USB Type-C |

| Dimensions | (Not specified) | 287 mm (L), 110 mm (H), 51 mm (W) |

| Release Date | 2021-05-30 | 2022-11-02 |

| Predecessor | Polaris Mobile | Navi II |

| Successor | (None) | Navi IV |

| Generation | Navi Mobile (RX 6000M) | Navi III (RX 7000) |

| Codename | (None) | Plum Bonito |

| Launch MSRP | (None) | 999 USD |