AMD Radeon Pro W6600X vs AMD Radeon Pro W6900X Comparison

Head-to-Head Benchmarks

The recorded data contains one direct comparison between these two Apple MPX cards: Geekbench Metal. In that test, the AMD Radeon Pro W6900X scores 226,821, while the AMD Radeon Pro W6600X scores 107,342. That is a delta of 111.3%, meaning the W6900X more than doubles the W6600X in Metal compute performance. It is not a narrow margin; it is a complete tier separation.

Looking at the average benchmark scores, the W6900X holds a 168,574 average across Metal, OpenCL, and Vulkan tests, while the W6600X has an average of 107,342 based solely on its Metal result. The W6900X sits in the 97th percentile of all GPUs, whereas the W6600X sits in the 94th percentile. Both are high-end parts, but the percentile gap reflects how much faster the larger card is.

The W6900X outperforms several notable rivals in the database. It is 1.5% ahead of the NVIDIA RTX 4500 Ada Generation (166,094 average score), 2% ahead of the NVIDIA RTX A5500 (165,217), 2.2% ahead of the AMD Radeon PRO W7800 (164,894), and 3.7% ahead of the NVIDIA A100 PCIe 40 GB (162,504). These are not massive wins, but they show the W6900X holding a consistent edge over a spread of professional workstation cards.

The W6600X also has competitive positioning against its own nearest rivals. It is 0.6% ahead of the AMD Radeon Pro Vega II Duo (106,750) and 5.4% ahead of the NVIDIA Quadro RTX 6000 (101,872). It trails the AMD Radeon Pro Vega II by 2.1% (that card scores 109,617) and the AMD Radeon PRO W7900 by 3.1% (110,725). So the W6600X is not a slow card; it sits in a crowded band where several capable workstation GPUs trade blows within a few percentage points.

The head-to-head data records one win for the W6900X and zero wins for the W6600X. The only benchmark shared between the two is Geekbench Metal, and the W6900X wins it decisively. The W6600X does not have recorded OpenCL or Vulkan scores in the database, so no additional direct comparisons can be drawn from the available measurements.

The Verdict

The data supports a simple conclusion: the AMD Radeon Pro W6900X is the performance pick, and the AMD Radeon Pro W6600X is the efficiency pick. If the workload is Metal-heavy and the priority is raw compute throughput, the W6900X delivers 111.3% more performance in that specific test. There is no scenario in the recorded benchmarks where the W6600X beats the W6900X.

However, the W6600X is not without purpose. It consumes only 120 W, has a suggested PSU of 300 W, and occupies a dual-slot form factor. The W6900X consumes 300 W and asks for a 700 W PSU. For systems where power delivery or thermal headroom is constrained, the W6600X is the more practical fit. It still lands in the 94th percentile of all GPUs, so it is far from a weak card.

The W6900X is for users who need maximum Metal performance in a Mac chassis and have the power budget to support it. The W6600X is for users who need solid workstation-class performance without the large power draw. Both are end-of-life products with the same release date of 2021-08-02, so neither has a longevity advantage in terms of production status.

Architecture Differences

Both cards share the same fundamental architecture: RDNA 2.0, built on TSMC's 7 nm process. Both are from the Radeon Pro Mac generation (Navi II Series) and both use the Apple MPX bus interface. The similarity ends there.

The W6900X uses the Navi 21 chip with 26,800 million transistors on a 520 mm² die, giving a transistor density of 51.5M per mm². The W6600X uses the Navi 23 chip with 11,060 million transistors on a 237 mm² die, a density of 46.7M per mm². The W6900X is physically a much larger chip, which explains its higher transistor count and larger die size.

Compute resources differ substantially. The W6900X has 5,120 shading units, 320 texture mapping units, 128 ROPs, and 80 ray tracing cores. The W6600X has 2,048 shading units, 128 TMUs, 64 ROPs, and 32 RT cores. In every compute category, the W6900X has double or more than double the resources of the W6600X, matching the 111.3% Metal performance delta.

Clock behavior is interesting. The W6600X actually runs higher clocks: 2068 MHz base and 2479 MHz boost, compared to the W6900X's 1825 MHz base and 2171 MHz boost. The smaller chip clocks higher, but the larger chip has far more parallel hardware. The W6900X's FP32 throughput is 22.23 TFLOPS versus 10.15 TFLOPS for the W6600X. FP16 follows the same pattern: 44.46 TFLOPS for the W6900X versus 20.31 TFLOPS for the W6600X. Both use a 2:1 ratio for FP16.

Memory is another major divider. The W6900X carries 32 GB of GDDR6 on a 256 bit bus, delivering 512.0 GB/s of bandwidth. The W6600X carries 8 GB of GDDR6 on a 128 bit bus, delivering 256.0 GB/s. Both run the same 2000 MHz memory clock or 16 Gbps effective speed. The W6900X has exactly double the memory bus width and double the bandwidth, plus four times the capacity.

Pixel and texture rates tell the same story. The W6900X achieves 277.9 GPixel/s and 694.7 GTexel/s. The W6600X achieves 158.7 GPixel/s and 317.3 GTexel/s. The W6600X is no slouch in fill-rate tasks, but the W6900X is clearly ahead.

Both cards support DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. The W6900X has display outputs: 1x HDMI 2.1 and 4x Thunderbolt. The W6600X has no outputs, a notable difference for anyone planning to drive displays directly from the card. The W6900X measures 267 mm in length (10.5 inches) and 120 mm in height (4.7 inches). The W6600X has no recorded dimensions beyond being dual-slot.

FAQ

Q: Which card is faster in Geekbench Metal?

A: The AMD Radeon Pro W6900X scores 226,821 versus 107,342 for the W6600X, a delta of 111.3%.

Q: Do both cards use the same architecture?

A: Yes, both are RDNA 2.0 on TSMC's 7 nm process, but they use different chips: Navi 21 for the W6900X and Navi 23 for the W6600X.

Q: How much memory does each card have?

A: The W6900X has 32 GB of GDDR6 on a 256 bit bus with 512.0 GB/s bandwidth. The W6600X has 8 GB of GDDR6 on a 128 bit bus with 256.0 GB/s bandwidth.

Q: Can the W6600X drive displays?

A: No, the W6600X has no display outputs. The W6900X has 1x HDMI 2.1 and 4x Thunderbolt outputs.

Q: What are the power requirements?

A: The W6900X has a TDP of 300 W and a suggested PSU of 700 W. The W6600X has a TDP of 120 W and a suggested PSU of 300 W.

Q: Are these cards still in production?

A: No, both are end-of-life products, and both were released on 2021-08-02.

Q: How does the W6900X compare to NVIDIA workstation cards?

A: It is 1.5% ahead of the NVIDIA RTX 4500 Ada Generation, 2% ahead of the RTX A5500, and 3.7% ahead of the A100 PCIe 40 GB in average benchmark score.

Q: How does the W6600X compare to its nearest rivals?

A: It is 0.6% ahead of the AMD Radeon Pro Vega II Duo and 5.4% ahead of the NVIDIA Quadro RTX 6000, but 2.1% behind the AMD Radeon Pro Vega II and 3.1% behind the AMD Radeon PRO W7900.

Where Each One Wins

The W6900X wins in every recorded performance category. It has higher Metal performance (226,821 versus 107,342), higher average benchmark score (168,574 versus 107,342), higher FP32 (22.23 TFLOPS versus 10.15 TFLOPS), higher FP16 (44.46 TFLOPS versus 20.31 TFLOPS), higher pixel rate (277.9 GPixel/s versus 158.7 GPixel/s), higher texture rate (694.7 GTexel/s versus 317.3 GTexel/s), more memory (32 GB versus 8 GB), and more memory bandwidth (512.0 GB/s versus 256.0 GB/s). It also has more shading units, TMUs, ROPs, and RT cores.

The W6600X wins in efficiency-oriented categories. It has a TDP of 120 W versus 300 W, and a suggested PSU of 300 W versus 700 W. It clocks higher (2068 MHz base and 2479 MHz boost versus 1825 MHz and 2171 MHz) and is a dual-slot card, whereas the W6900X has no recorded slot width. The W6600X also uses a smaller die (237 mm² versus 520 mm²) with fewer transistors (11,060 million versus 26,800 million), which likely contributes to its lower power draw.

For users with Metal-based workloads and no display-output requirement, the W6600X offers a meaningful performance tier at a fraction of the power draw. For users who need display outputs, the W6900X is the only option of the two, since the W6600X has none. For large datasets that exceed 8 GB, the W6900X's 32 GB frame buffer is essential; the W6600X would be limited by its 8 GB capacity.

The percentile rankings confirm the split: the W6900X sits at the 97th percentile of all GPUs, while the W6600X sits at the 94th. Both are high performers, but the W6900X is in a different league. The W6600X's nearest rivals include the Radeon Pro Vega II Duo and the Radeon PRO W7900, which shows it competes with older flagship cards. The W6900X's nearest rivals are the RTX 4500 Ada Generation and RTX A5500, which shows it competes with current-generation professional hardware.

Specification Differences

| Specification | AMD Radeon Pro W6900X | AMD Radeon Pro W6600X |

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

| Chip | Navi 21 | Navi 23 |

| Process Node | 7 nm | 7 nm |

| Transistors | 26,800 million | 11,060 million |

| Die Size | 520 mm² | 237 mm² |

| Transistor Density | 51.5M / mm² | 46.7M / mm² |

| Base Clock | 1825 MHz | 2068 MHz |

| Boost Clock | 2171 MHz | 2479 MHz |

| Memory Clock | 2000 MHz (16 Gbps effective) | 2000 MHz (16 Gbps effective) |

| Memory Size | 32 GB | 8 GB |

| Memory Type | GDDR6 | GDDR6 |

| Memory Bus Width | 256 bit | 128 bit |

| Memory Bandwidth | 512.0 GB/s | 256.0 GB/s |

| Shading Units | 5120 | 2048 |

| TMUs | 320 | 128 |

| ROPs | 128 | 64 |

| RT Cores | 80 | 32 |

| Pixel Rate | 277.9 GPixel/s | 158.7 GPixel/s |

| Texture Rate | 694.7 GTexel/s | 317.3 GTexel/s |

| FP32 | 22.23 TFLOPS | 10.15 TFLOPS |

| FP16 | 44.46 TFLOPS (2:1) | 20.31 TFLOPS (2:1) |

| TDP | 300 W | 120 W |

| Suggested PSU | 700 W | 300 W |

| Slot Width | Not recorded | Dual-slot |

| Display Outputs | 1x HDMI 2.1, 4x Thunderbolt | No outputs |

| Dimensions | 267 mm (10.5 inches) length, 120 mm (4.7 inches) height | Not recorded |

| Launch MSRP | 5,999 USD | 699 USD |

| Release Date | 2021-08-02 | 2021-08-02 |

| Production Status | End-of-life | End-of-life |

The specification table shows that both cards share the same architecture generation, process node, memory type, API support, bus interface, and release date. Everything else falls into two tiers. The W6900X doubles or quadruples the W6600X in memory capacity, bandwidth, compute units, and power draw. The W6600X counters with higher clocks, a smaller die, and a much lower power envelope. Neither card supports tensor cores, and both are end-of-life.

The launch MSRP difference is stark: 5,999 USD for the W6900X versus 699 USD for the W6600X. That price gap reflects the massive hardware disparity, but the database makes no judgment on cost effectiveness. The performance data alone shows a 111.3% Metal lead for the W6900X, while the power data shows a 180 W TDP advantage for the W6600X. Buyers should weigh those two facts according to their own system constraints.