The secret of the Apple M5 Ultra may have been revealed

We’ve been waiting for Apple to release the M5 Pro and M5 Max MacBook Pro for weeks, sometime after the release of macOS 26.3. Now that the release candidates for 26.3 are available, we should see these new MacBooks next week. But there’s one more bit of intrigue: based on the code inside, light was shed on another chip we’ve all been wondering about.

According to a MacRumors report, the iOS 26.3 release candidate includes references to the M5 Max and M5 Ultra chips. Code no expressly say “M5 Max” or “M5 Ultra”, but rather refers to the model and platform codes that correspond to those chip families (model numbers T6051 and T6052 with associated platform names H17C and H17D). The “17” is a reference to the M5 (H17G), while the “C” and “D” refer to the Max and Ultra chips. Curiously, the letter “S” used for Pro chips is not listed in the code.

Assuming Apple hasn’t changed the encoding system, this revelation lets us know that yes, Apple is testing Macs with the M5 Ultra chip. Apple didn’t release the M4 Ultra for Mac Studio in March 2024. Instead, the company went with the M3 Ultra, which, despite being an older generation, is currently Apple’s fastest chip. Apple has never publicly explained why it went in this direction, or why the Mac Pro stuck with the M2 Ultra.

At the time, the M3 Ultra left us wondering about the next Ultra chip: will it be the M4 or the M5? Well, it looks like we already know. But what about the M5 Pro? It’s possible that Apple simply left the link out and could add it later when the software is released. Another possibility is that Apple changed the names and the “D” reference actually refers to the M5 Pro (which makes this whole article moot). The last possibility is that Apple will release the M5 Ultra MacBook Pro, which would be the first time.