iPhone 18 may miss Apple's most advanced AI features — Here's why

Amid growing anticipation for Apple's all-new iPhone 18 lineup, expected to debut this fall, a steady stream of leaks and analyst insights has kept excitement among enthusiasts at a fever pitch. In the latest development, Apple is expected to unveil the iPhone 18 Pro and iPhone 18 Pro Max this fall, possibly alongside its first-ever foldable iPhone. The standard iPhone 18, meanwhile, is reportedly slated to arrive later in Spring 2027 alongside the iPhone 18e.

While the entire lineup is expected to receive a RAM upgrade, the increase may still not be enough for the standard iPhone 18 to support Apple's upcoming Siri AI features.

The key limitation lies with Apple's AFM (Apple Foundation Models) Core Advanced model. The on-device AI model powers several new features, including Advanced Dictation Preview in iOS 27 and Apple's new Expressive Siri Voices. Since the model runs locally on supported devices, it reportedly requires at least 12GB of RAM to function.

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Sharing his latest insight, TF International Securities analyst Ming-Chi Kuo said that the lower-end iPhone 18 models powered by Apple's A20 chip are expected to feature 9GB of RAM, up from the 8GB found in current standard iPhone models.

Advanced Dictation Preview is currently available only on the iPhone 17 Pro, iPhone 17 Pro Max, and iPhone 17 Air running the iOS 27 beta. The standard iPhone 17, along with the iPhone 16 Pro lineup, is excluded, as both feature 8GB of RAM.

The Advanced Dictation Preview feature improves transcription accuracy by automatically handling punctuation and capitalization as users speak. Meanwhile, Expressive Siri Voices are designed to make Apple's digital assistant sound more natural, fluid, and conversational. If the reported 12GB RAM requirement remains unchanged, these advanced Siri capabilities are unlikely to make their way to the standard iPhone 18 models.

The Pro models could maintain the advantage

Apple has yet to officially announce the iPhone 18 lineup, meaning the final hardware split remains unconfirmed. However, according to analyst Ming-Chi Kuo, the iPhone 18 Pro, iPhone 18 Pro Max, and Apple's long-rumored foldable iPhone are all expected to feature 12GB of RAM.

At first glance, the distinction may appear to be another attempt by Apple to push buyers toward its premium Pro models. However, the memory allocation is also being influenced by broader supply chain constraints rather than product segmentation alone.

With RAM prices continuing to climb, Apple has already increased prices across parts of its iPad and Mac lineup. The upcoming iPhone 18 Pro models are likewise expected to carry a price increase of around $200.

Meanwhile, Apple is reportedly seeking regulatory approval to source memory chips from Chinese manufacturer CXMT as it looks to ease ongoing supply constraints that have made it increasingly difficult to equip lower-cost iPhones with the memory needed to run advanced on-device AI features.