Apple's highest-end M3 Ultra chip is currently limited to the Mac Studio, but a new leak has revealed that Apple tested the chip in the MacBook Pro as well.
In a post today on the Chinese social media platform BiliBili, a user who we are not familiar with said that they found code references to unreleased 14-inch and 16-inch MacBook Pro models with the M3 Ultra chip, in an internal build of iOS 18 running on an iPhone 16 engineering prototype. Specifically, they said that they found J514d and J516d codenames in a file located in the /AppleInternal/Diags/Tests/ folder.
J514 and J516 are the codenames for the 14-inch and 16-inch MacBook Pro models with M3 Pro and M3 Max chips, which were introduced by Apple in October 2023. However, these particular codenames have a "d" suffix, which likely refers to an Ultra chip. For example, the Mac Studio with the M3 Ultra is codenamed J575d.
Apple has never released a MacBook Pro with an Ultra chip, so this is a noteworthy discovery.
Currently, the M3 Ultra is the fastest Mac chip that Apple has ever released. It features up to a 32-core CPU, up to an 80-core GPU, and support for up to 512GB of unified memory, so those could have been MacBook Pro specs in an alternate universe.
Instead, Apple updated the 14-inch and 16-inch MacBook Pro models with M4, M4 Pro, and M4 Max chip options in October last year. Apple most likely decided not to make the M3 Ultra chip available in the MacBook Pro, potentially due to greater thermal and battery life impacts for laptops compared to desktop computers.
With the M4 Max, the MacBook Pro can be configured with up to a 16-core CPU, up to a 40-core GPU, and up to 128GB of unified memory.
All in all, it appears that Apple at least considered MacBook Pro models with the M3 Ultra chip, but it is unlikely that they will ever be released.
