AMD’s Apple-exclusive dual GPU defeats RTX 4080 in head-to-head benchmark

In context: In 2021, Apple worked with AMD to produce new Mac Pro computers with the most powerful graphics card ever found in an Apple computer. The Radeon Pro W6800X Duo had long been exclusive to Apple hardware until der8auer discovered a way to use the GPU outside the Apple ecosystem.

Apple knew it had acquired something special with the Radeon Pro W6800X Duo since the graphics card costs $5,000 on their website. It features two Navi 21 dies connected through AMD’s Infinity Fabric, albeit with 20 compute units disabled on both dies. The GPU also has 32 GB of GDDR6 memory and a 128 MB Infinity Cache.

For perspective, the Navi 21 die is found on both of AMD’s RDNA2 flagships, the RX 6900 XT and RX 6950 XT. This die is already a powerhouse, as demonstrated by our benchmarks. As one would expect, placing two onto Apple’s GPU makes it a monster, despite slightly hindered performance on each die.

With the W6800X Duo nearly being a dual-card 6900 XT, many people were curious about the card’s capabilities. One of these was Roman Hartung, the renowned extreme overclocker der8auer. In a recent video, der8auer tore down and tested a W6800X Duo, though with numerous difficulties.

While the GPU uses a standard PCIe x16 slot commonly found on consumer motherboards, the power delivery is anything but typical. The card features Apple’s proprietary Mac Pro eXpansion (MPX) module rather than a standard PCIe power connector. Despite this, der8auer repurposed a 12VHPWR cable to provide the 400 watts the W6800X Duo requires.

After tackling numerous issues, including failed driver installations, high temperatures, and finicky power delivery, der8auer finally got the GPU in working order. As seen above, the card needed many modifications and soldering to operate on a standard motherboard. Despite this, the GPU struggled to finish the benchmark, suffering numerous crashes and shutdowns.

After many attempts, Hartung managed to push the card to complete the benchmark. In 3DMark TimeSpy, the W6800X Duo performed admirably, clocking in at an average FPS of 97.21. While this is 21 percent slower than Nvidia’s RTX 4090, it edges out the RTX 4080 by just over four percent. It also defeats AMD’s flagship RX 7900 XTX by about eight percent.

Overall, the results shown by the W6800X Duo are impressive. It does raise the question of why this card or a similar variant never reached the consumer market and instead was restricted to a $5,000 purchase within the Mac ecosystem. Regardless, der8auer’s work is greatly appreciated, as it didn’t come cheap.