It's a pity that the Radeon Pro W6800X Duo didn't make it outside Apple's ecosystem. Given its latest performance show, the dual Navi 21-based offering from AMD would rival the best graphics cards on the market.
The Radeon Pro W6800X Duo features not one but two Navi 21 (Sienna Cichlid) dies. They communicate with each other via AMD's Infinity Fabric interconnect. Unfortunately, AMD didn't let the Radeon Pro W6800X Duo leverage the full Navi 21 silicon. Instead, the chipmaker disabled 20 CUs (compute units) from each Navi 21, leaving the Radeon Pro W6800X Duo with just 60 CUs or 3,840 SPs (stream processors). Each Navi 21 dies also arrives with 32GB of 16 Gbps GDDR6 memory across a 256-bit memory interface and 128MB of Infinity Cache.
AMD produced the Radeon Pro W6800X Duo specifically for the Mac Pro; therefore, the graphics card adopts Apple's proprietary MPX (Mac Pro eXpansion) form factor. The expansion module has no external power connectors, so Apple combines a standard PCIe x16 connector and a custom connector for added power delivery. The Radeon Pro W6800X Duo has a 400W, so a single PCIe x16 expansion slot isn't enough to provide the graphics card with enough juice.
Distinguished extreme overclock Roman "der8auer" Hartung (opens in new tab) got the Radeon Pro W6800X Duo to work on a standard motherboard with some clever modifications. First, he connected the graphics card to the PCIe expansion slot using a regular PCIe x16 riser cable and subsequently soldered two 12V and two ground wires from his 12VHPWR cable to the Apple connector.
Radeon Pro W6800X Duo Benchmarks
|Graphics Card||Time Spy Extreme Score|
|GeForce RTX 4090 FE||123.49|
|Radeon Pro W6800X Duo||97.21|
|Asus Strix GeForce RTX 4080||93.28|
|Radeon RX 7900 XTX (MBA)||89.78|
|Gigabyte Eagle GeForce RTX 4070 Ti||69.78|
Hartung tested the Radeon Pro W6800X Duo on his latest Z790 platform with the Core i9-13900K and 32GB (2x16GB) of DDR5-6000 C30 memory. He specifically used 3DMark's Time Spy Extreme GT1 benchmark for comparison. Surprisingly, the regular Adrenalin drivers refused to install, implying that the Radeon Pro W6800X Duo isn't intended to work on a non-Apple device. However, Hartung found success with the Apple Boot Camp driver.
The Radeon Pro W6800X Duo delivered 4% higher performance than the Asus Strix GeForce RTX 4080. The RDNA 2 graphics card also outperformed AMD's latest Radeon RX 7900 XTX by 8%. Only the GeForce RTX 4090 could beat the Radeon Pro W6800X Duo. The Ada Lovelace flagship beat the Radeon Pro W6800X Duo by a significant 27% margin.
Radeon Pro W6800X Duo is a graphics card for professional users, but it's always cool to see how the hardware performs in gaming. Apple sells the Radeon Pro W6800X Duo MPX Module for $5,000, so it's not a toy that everyone can acquire to play with. Although Hartung paid slightly less for his Radeon Pro W6800X Duo, kudos to him for buying one to show us how it fares against modern graphics cards, even if it's just a generic gaming benchmark.
I wonder if a dual RX 6900 XT could've even bested a RTX 4090. That'd be 33% more CU's. If it scaled really linearly, then it could just squeak past the 27% margin held by the Nvidia card.
I'm not sure how you can compare if you cant do SLI
I'd hazard a guess that the software sees it as two RX 6800 GPUs on a PCI bridge, with a Crossfire link between them.
I tend to doubt it is using CFX technology, which never worked on Mac that I can recall, OGL or Metal. It might actually be seen as one gpu.