--- title: My thousand dollar iPhone can't do math | daily.dev description: An iPhone 16 Pro Max produced incorrect numerical outputs when running MLX-based LLMs, while the same code worked perfectly on an iPhone 15 Pro and MacBook... canonical: https://daily.dev/posts/my-thousand-dollar-iphone-can-t-do-math-8plwg9hzb twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: My thousand dollar iPhone can't do math | daily.dev og:description: An iPhone 16 Pro Max produced incorrect numerical outputs when running MLX-based LLMs, while the same code worked perfectly on an iPhone 15 Pro and MacBook... og:url: https://daily.dev/posts/my-thousand-dollar-iphone-can-t-do-math-8plwg9hzb og:image: https://api.daily.dev/og/posts/8PlWg9hZB.png og:image:alt: My thousand dollar iPhone can't do math og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # My thousand dollar iPhone can't do math **[Hacker News](https://daily.dev/sources/hn)** · 9 min read · 0 upvotes · 0 comments ## Summary An iPhone 16 Pro Max produced incorrect numerical outputs when running MLX-based LLMs, while the same code worked perfectly on an iPhone 15 Pro and MacBook Pro. Through systematic debugging involving breakpoint analysis and tensor output comparison across devices, the issue was traced to a hardware defect in the A18 chip's Neural Engine or ML accelerator. The tensor values were orders of magnitude off during computation, despite identical inputs. The problem was confirmed as device-specific hardware failure when a replacement iPhone 17 Pro Max ran the same code correctly. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Your Local LLM Could Be Leaving Mac Performance on the Table](https://daily.dev/posts/your-local-llm-could-be-leaving-mac-performance-on-the-table-fxxfy93gy) · Medium · 0 upvotes · 0 comments - [My phone runs local LLMs faster than my gaming PC, and it's the setup I actually reach for every day](https://daily.dev/posts/my-phone-runs-local-llms-faster-than-my-gaming-pc-and-it-s-the-setup-i-actually-reach-for-every-day-awjwcjgjy) · XDA Developers · 0 upvotes · 0 comments --- Tags: [#machine-learning](https://daily.dev/tags/machine-learning), [#apple](https://daily.dev/tags/apple), [#ios](https://daily.dev/tags/ios) [View this post on daily.dev](https://daily.dev/posts/my-thousand-dollar-iphone-can-t-do-math-8plwg9hzb) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"My thousand dollar iPhone can't do math","url":"https://daily.dev/posts/my-thousand-dollar-iphone-can-t-do-math-8plwg9hzb","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/my-thousand-dollar-iphone-can-t-do-math-8plwg9hzb"},"datePublished":"2026-02-02T00:18:53.050Z","dateModified":"2026-02-02T00:19:15.769Z","description":"An iPhone 16 Pro Max produced incorrect numerical outputs when running MLX-based LLMs, while the same code worked perfectly on an iPhone 15 Pro and MacBook...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/9382818207bd7fade230f0efbe26da4c?_a=AQAEulh","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/9382818207bd7fade230f0efbe26da4c?_a=AQAEulh","isAccessibleForFree":true,"articleSection":"Hacker News","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Hacker News","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/hn","url":"https://daily.dev/sources/hn"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/my-thousand-dollar-iphone-can-t-do-math-8plwg9hzb","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"machine-learning,apple,ios","timeRequired":"PT9M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Hacker News","item":"https://daily.dev/sources/hn"},{"@type":"ListItem","position":3,"name":"My thousand dollar iPhone can't do math"}]} ```