--- title: Grok 4.5 (Fully Tested Vs GPT-5.6 Sol & Fable): IT'S... description: Grok 4.5, xAI's new 1.5 trillion parameter mixture-of-experts model, is reviewed and benchmarked against GPT-5.6, Claude Fable 5, and Opus 4.8. Trained in... canonical: https://daily.dev/posts/grok-4-5-fully-tested-vs-gpt-5-6-sol-fable-it-s-actually-good--d6i4ugzvn twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Grok 4.5 (Fully Tested Vs GPT-5.6 Sol & Fable): IT'S ACTUALLY GOOD! | daily.dev og:description: Grok 4.5, xAI's new 1.5 trillion parameter mixture-of-experts model, is reviewed and benchmarked against GPT-5.6, Claude Fable 5, and Opus 4.8. Trained in... og:url: https://daily.dev/posts/grok-4-5-fully-tested-vs-gpt-5-6-sol-fable-it-s-actually-good--d6i4ugzvn og:image: https://api.daily.dev/og/posts/d6I4uGZvN.png og:image:alt: Grok 4.5 (Fully Tested Vs GPT-5.6 Sol & Fable): IT'S ACTUALLY GOOD! 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. # Grok 4.5 (Fully Tested Vs GPT-5.6 Sol & Fable): IT'S ACTUALLY GOOD! **[AICodeKing](https://daily.dev/sources/aicodeking)** · 12 min read · 0 upvotes · 0 comments ## Summary Grok 4.5, xAI's new 1.5 trillion parameter mixture-of-experts model, is reviewed and benchmarked against GPT-5.6, Claude Fable 5, and Opus 4.8. Trained in collaboration with Cursor (acquired by xAI) on trillions of tokens of real developer/agent interactions plus RL on multi-step software engineering tasks, it scores 51/70 (72.86%) in a 7-question coding test — placing fifth overall but ahead of Sonnet 5 and Opus 4.7. Key strengths include frontier-level hard reasoning, strong agentic task completion, and exceptional token efficiency (~2M tokens per task vs ~7-9M for competitors), making it roughly 31 cents per task vs $2.75 for Fable 5. Priced at $2/$6 per million input/output tokens, it offers roughly 85% of Opus 4.8's performance at a fraction of the cost. Weaknesses include overthinking on puzzle tasks, weaker 3D/visual generation, and lack of multi-agent orchestration capability compared to Fable 5 and GPT-5.6. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How much does Grok 4.5's API cost compared to Fable 5? Grok 4.5 costs $2 per million input tokens and $6 per million output tokens, roughly five to eight times cheaper than Fable 5's $10 input and $50 output per million tokens. Cached input drops to $0.50 per million, a 75% discount. Pricing doubles to $4 input and $12 output once context exceeds 200k tokens. _Developers comparing model pricing before committing to an API can track cost breakdowns like this on daily.dev._ ### How many parameters does Grok 4.5 have and how was it trained? Grok 4.5 is a 1.5 trillion parameter mixture-of-experts model, a full pre-training run from scratch rather than a fine-tune of earlier Grok models, which were around 500 billion parameters. It was trained on tens of thousands of Nvidia's GB300 GPUs, using trillions of tokens of Cursor data plus reinforcement learning on hundreds of thousands of multi-step software engineering tasks. _Anyone weighing which model to build agentic coding workflows on can follow releases like this via daily.dev._ ### How token-efficient is Grok 4.5 compared to Fable 5 and Opus 4.8 on coding tasks? Grok 4.5 uses about 2 million tokens per coding task, versus roughly 7 million for Fable 5 and 9 million for Opus 4.8. In cost terms, that works out to about 31 cents per task for Grok compared to about $2.75 for Fable 5 doing the same work, giving Grok a major cost advantage in agentic coding. _Teams estimating agentic coding costs across models can keep tabs on efficiency comparisons through daily.dev._ ## Similar posts on daily.dev - [Grok 4.5 vs Claude Fable 5 vs GPT-5.6 Sol: How I’m Testing Them Across 100 Real Tasks](https://daily.dev/posts/grok-4-5-vs-claude-fable-5-vs-gpt-5-6-sol-how-i-m-testing-them-across-100-real-tasks-hb5pgi2wo) · Medium · 0 upvotes · 0 comments --- Tags: [#ai](https://daily.dev/tags/ai), [#llm](https://daily.dev/tags/llm), [#ai-coding](https://daily.dev/tags/ai-coding), [#grok](https://daily.dev/tags/grok) [View this post on daily.dev](https://daily.dev/posts/grok-4-5-fully-tested-vs-gpt-5-6-sol-fable-it-s-actually-good--d6i4ugzvn) ```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":"Grok 4.5 (Fully Tested Vs GPT-5.6 Sol & Fable): IT'S ACTUALLY GOOD!","url":"https://daily.dev/posts/grok-4-5-fully-tested-vs-gpt-5-6-sol-fable-it-s-actually-good--d6i4ugzvn","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/grok-4-5-fully-tested-vs-gpt-5-6-sol-fable-it-s-actually-good--d6i4ugzvn"},"datePublished":"2026-07-10T09:29:01.183Z","dateModified":"2026-09-13T19:39:07.537Z","description":"Grok 4.5, xAI's new 1.5 trillion parameter mixture-of-experts model, is reviewed and benchmarked against GPT-5.6, Claude Fable 5, and Opus 4.8. 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