Apple’s most powerful M3 Ultra chip is currently only available in the Mac Studio, but a new leak suggests that the company also tested the chip in MacBook Pro models. The leak reportedly originates from a BiliBili user who stumbled upon code strings pointing to unannounced 14- and 16-inch MacBook Pro models powered by the M3 Ultra chip. These references were discovered in an internal build of iOS 18 installed on an iPhone 16 engineering prototype.

Apple reportedly tested the M3 Ultra chip in unreleased MacBook Pro models, but it likely won’t launch them

More specifically, the leak is referring to the J514d and J516d codenames, which are filed under /AppleInternal/Diags/Tests/ directory. Apple’s 14-inch and 16-inch MacBook Pro models with M3 Pro and M3 Max chips introduced in October 2023 are known by the codenames J514 and J516, respectively.

The addition of the “d” suffix would presumably represent versions with the Ultra chip, just like the Mac Studio’s M3 Ultra codename J575d. It is worth mentioning that Apple has never launched an Ultra chip-powered MacBook Pro, so this alleged leak sounds particularly fascinating.

What hasn’t changed is the fact that M3 Ultra is the fastest Mac chip Apple has ever built, available with up to a 32-core CPU, an 80-core GPU, and up to 512GB of unified memory. These specs suggest what would have been possible for a MacBook Pro, had Apple opted to include the chip in a laptop.

Apple did update its 14-inch and 16-inch MacBook Pro lineup with M4, M4 Pro, and M4 Max chips last October, though. The reason M3 Ultra isn’t found in laptops is probably because of the extra heat it generates and the effect that has on battery life, a bigger concern with a portable device than on a desktop.

Currently, the M4 Max-equipped MacBook Pro can be configured with up to a 16-core CPU, 40-core GPU, and 128GB of unified memory. In conclusion, while Apple considered M3 Ultra MacBook Pros, it seems unlikely these models will ever hit the market.