Claude Opus 5.5 Tops AA Index as Faster, Cheaper Model Sparks Buzz

Claude Opus 5.5 launched on September 23 and immediately topped the Artificial Analysis intelligence index by a clear margin, while Anthropic cut prices and deepened cache-hit discounts. First-hand feedback from developers and researchers has been broadly positive: roughly 30% faster than Opus 5 and about 40% cheaper per task; some users cite a 25% price drop versus the previous generation and 3x cheaper than Fable — the reported discount figures range from 20% to 40%, pending official pricing details. Whichever number you pick, the community consensus is a clear boost in value, worth the attention of every heavy Claude Code user.

Confirmed

• Opus 5.5 took first place on the Artificial Analysis Intelligence Index, with multiple posts citing leaderboard screenshots; per AAII data relayed by Angaisb, its overall intelligence score leads by a wide margin, and at the xhigh reasoning tier it outscores Fable 5.1 Max while using fewer tokens.
• Multiple independent testers report consistent efficiency figures: developer Lydia Hallie and AI researcher Yuchen Jin both cite 30% faster than Opus 5 and 40% cheaper per task.
• Coding highlights: per minchoi and vista8, Opus 5.5 audited and fixed a 200K-line codebase in under 3 hours (Opus 5 needed 20+ hours), with 2.5x fewer tokens and about one-fifth the cost of GPT-6 Astra; another early tester completed a 680K-line code migration. Benchmarks via vista8: 66.4% on Terminal-Bench 4.0, 54.4% on FrontierCode v1.1, and 57.8% on CursorBench 4.0.
• Anthropic's Alex Albert praised the model as smart, clear in writing, fast, and far cheaper; developer bindureddy found many tasks nailed in a single pass; doodlestein saw strong results on multi-project tasks and is cautiously optimistic.

Unconfirmed

• Per a leak relayed by airesearch12, Opus 5.5 (max with fallback) scores 58 on the intelligence index, 5 points ahead of the previous SoTA — pending verification on the official leaderboard.
• Some benchmark comparisons (e.g., comprehensively beating Fable 5.1 and GPT-6 Astra) come from secondhand blogger reports and await official confirmation.

Why it matters

• Rival Fable 5.1 and Astra launched just three weeks ago and have already been overtaken — danielmac8 and other users marveled at the pace of model iteration, as the lead window for top models keeps shrinking.
• A clear price-war signal: benchmark supremacy plus price cuts directly reshapes the cost-benefit math for enterprise API selection.
• Not without controversy: researcher Nat Lambert points out that Opus 5.5 has the highest per-task token consumption of all models tested, which he believes explains Anthropic's price cut — and makes the top ranking a "red flag"; Angaisb also recalls that Opus 5 scored high but underwhelmed in practice, so final reputation remains to be seen.

2026-09-23 ~ 2026-09-23 · 30 related posts

Full story(5 episodes)→

• Episode 1: Claude Opus 5.5 Spotted in Claude Code Ahead of Launch(2026-09-23, 3 posts)
• Episode 2: Anthropic Launches Claude Opus 5.5, Cheaper and Smarter(2026-09-23, 60 posts)
• Episode 3: Claude Opus 5.5 Tops AA Index as Faster, Cheaper Model Sparks Buzz(2026-09-23, 30 posts)
• Episode 4: Anthropic Launches Opus 5.5, Leading in Agentic Coding and Computer Use(2026-09-23, 5 posts)
• Episode 5: Anthropic Teases Sonnet 5.5 and Haiku 5.5 Within Weeks(2026-09-23, 2 posts)

• Opus 5.5 benchmarks: beats Fable 5.1 and GPT 6 Astra at half the price — Scobleizer · 2026-09-23
• Opus 5.5 posts strong benchmarks, but the Opus 5 precedent looms over GPT-6 Sol fears — Angaisb_ · 2026-09-23
• Hands-on With Opus 5.5: Same Feel as 4.6, More Power, ~40% Cheaper Than Opus 5 — EricBuess · 2026-09-23
• Anthropic staffer calls Opus 5.5 fast, cheap and 'a very good model' — alexalbert__ · 2026-09-23
• [source] Hands-on with Opus 5.5: feels like Fable, ~30% faster and ~40% cheaper per task than Opus 5 — lydiahallie · 2026-09-23
• Claude Opus 5.5 tops Artificial Analysis Intelligence Index with 20% price cut — minxio_ · 2026-09-23
• Dev Praises Claude Opus 5.5: One-Shot Success, Faster and Cheaper Than Opus 5 — bindureddy · 2026-09-23
• Claude Opus 5.5 Tops AI Index at 58, Cuts Price 20% to Match GPT-6 Astra — brandon_galang · 2026-09-23
• Opus 5.5 is ~30% faster and ~40% cheaper per task than Opus 5, researcher says — Yuchenj_UW · 2026-09-23
• Opus 5.5 Leads Artificial Analysis Intelligence Index by a Wide Margin — Angaisb_ · 2026-09-23
• [source] Opus 5.5 Jumps to 1st Place on the AA Intelligence Index — UnknownEssence · 2026-09-23
• Opus 5.5 Lauded as One-Shot Machine, 25% Cheaper Than Opus 5 — bindureddy · 2026-09-23
• Claude Opus 5.5 lands in Hermes Agent, claims sweep of Fable 5.1 and GPT 6 Astra at half the price — NousResearch · 2026-09-23
• Opus 5.5 is 40% cheaper and 30% faster than Opus 5, says Reddit post — Seeker_Of_Knowledge2 · 2026-09-23
• Opus 5.5 ships ~30% faster and ~40% cheaper per task than Opus 5 — haider1 · 2026-09-23
• AAII ranking: Opus 5.5 tops overall intelligence, beats Fable 5.1 Max with fewer tokens at xhigh — Angaisb_ · 2026-09-23
• Leak: Claude Opus 5.5 reportedly scores 58 on AA Intelligence Index, 5 points over SoTA — airesearch12 · 2026-09-23
• [source] Nat Lambert flags Opus as top token-gobbler: leading the Intelligence Index is a red flag — natolambert · 2026-09-23
• Anthropic ships Opus 5.5: up to 40% cheaper than Opus 5, pulling Codex users back to Claude — danshipper · 2026-09-23
• Claude Opus 5.5 dominates benchmarks of rivals released three weeks ago — daniel_mac8 · 2026-09-23
• Opus 5.5 field results: 200k-line codebase fixed in under 3 hours at 1/5 the cost of GPT-6 Astra — vista8 · 2026-09-23
• Opus 5.5 audits a 200k-line codebase in under 3 hours using 2.5x fewer tokens than Opus 5 — minchoi · 2026-09-23
• Early hands-on: Opus 5.5 strong across tasks, reportedly 3x cheaper than Fable — doodlestein · 2026-09-23
• Early users: Opus 5.5 is ~3x cheaper than Fable with much higher Max usage — doodlestein · 2026-09-23
• Artificial Analysis: Opus 5.5 Outperforms Fable 5.1 While Costing Less — alex_teichman · 2026-09-23
• Opus 5.5 tops the charts while undercutting Astra and Fable on price — MatthewBerman · 2026-09-23
• Claude Opus 5.5 takes #1 on Artificial Analysis, now available in Claude Code — ccerrato147 · 2026-09-23

3 near-duplicate retellings: danshipper · every · every