ResearchLLM Verifications Leaderboard

Data as of · 78 models, 80 questions · reviewed by Suhas Bhairav · methodology

Head to head · tested 27 Oct 2026

Claude Fable 5.1 vs Gemini 4 Argon: accuracy, speed and price

Similar accuracy; Gemini 4 Argon costs less per question.

AnthropicClaude Fable 5.181.2% score · #5$0.016 per question70 tok/sGoogleGemini 4 Argon83.8% score · #2$0.0062 per question69 tok/s

Verdict

Built from the measurements below

  • Accuracy is too close to call: Claude Fable 5.1 scored 81.2% and Gemini 4 Argon 83.8% on the same 80 questions, a gap within what chance alone could produce.
  • Gemini 4 Argon is 2.6× cheaper per question as billed ($0.0062 vs $0.016), reasoning tokens included.
  • Output speed is similar (70 vs 69 tokens per second).
  • Claude Fable 5.1 starts answering sooner: 2.1 s to the first token, against 3.3 s for Gemini 4 Argon.

Which should you choose?

Choose Claude Fable 5.1 for a quicker first token, shorter outputs (about 238 tokens per question against 558) and more hosts to choose from on OpenRouter (4 against 2). Choose Gemini 4 Argon for the lower cost per correct answer ($0.0074 against $0.02).

Accuracy gap -2.5 points (z = -0.42). A winner is called only when z is at least 1.96, the usual 95% threshold. Speed, latency and price need a 10% margin.

Head to head

Same questions, same prompt, same API

MeasureClaude Fable 5.1Gemini 4 ArgonEdge
Verification scoreHigher is better81.2%83.8%Too close to call
Cost per questionLower is better$0.016$0.0062Gemini 4 Argon
Output speedHigher is better7069Similar
Time to first tokenLower is better2.1 s3.3 sClaude Fable 5.1
End-to-end response timeLower is better11.0 s9.9 sGemini 4 Argon
Tokens per questionLower is better238558Claude Fable 5.1
Context windowHigher is better1M1MSimilar

Side by side

Bars are scaled to the larger of the two values. The winner on each measure is marked in bold.

Every measure

Claude Fable 5.1 first, Gemini 4 Argon second

Verification scorehigher is better
Claude Fable 5.181.2%
Gemini 4 Argon83.8%
Cost per questionlower is better
Claude Fable 5.1$0.016
Gemini 4 Argon$0.0062
Output speedhigher is better
Claude Fable 5.170
Gemini 4 Argon69
Time to first tokenlower is better
Claude Fable 5.12.1 s
Gemini 4 Argon3.3 s
End-to-end response timelower is better
Claude Fable 5.111.0 s
Gemini 4 Argon9.9 s
Tokens per questionlower is better
Claude Fable 5.1238
Gemini 4 Argon558
Context windowhigher is better
Claude Fable 5.11M
Gemini 4 Argon1M

Score vs. cost per question

Both models in color, every other model in grey

Most attractive quadrant0255075100$0.00001$0.0001$0.001$0.01$0.10Cost per question (USD, log) →Verification score (%) →Qwen3.8 2.4T A95BCommand AReka Flash 3Gemma 4 26B A4BGemma 4 31BQwen3.5 397B A17BHermes 4 405BClaude Fable 5.1Grok 4.7o3gpt-oss-20bMinistral 3 3B 2512Nova Micro 1.0Phi 4Granite 4.2 8BHy3GLM 5.3 FlashSolar Pro 4Trinity Large ThinkingMiniMax M3Mistral Large 4Claude Opus 5.5GPT-6.1 SolGemini 4 ArgonGPT-6 Lunagpt-oss-120bLlama 4 MaverickQwen3.8 Max (0902)

Specifications and pricing

From OpenRouter's catalogue, plus the leaderboard's test dates

SpecificationClaude Fable 5.1Gemini 4 Argon
CreatorAnthropicGoogle
Released1 Sept 202613 Oct 2026
Weights——
ReasoningYesYes
Inputtext, image, fileaudio, file, image, text, video
Outputtexttext
Context window1M tokens1M tokens
Knowledge cutoff——
List price in / out per 1M$10 / $50$2 / $10
Blended price per 1M (3:1)$20.00$4.00
Cheapest hostAzure · $10 / $50Google AI Studio · $1 / $5
Hosts on OpenRouter42
Last tested27 Oct 202625 Oct 2026

Compare any two models →

Claude Fable 5.1 vs Gemini 4 Argon: frequently asked questions

Is Claude Fable 5.1 better than Gemini 4 Argon?
On accuracy they are statistically tied: Claude Fable 5.1 scored 81.2% and Gemini 4 Argon 83.8% on the same 80 questions from open datasets. Similar accuracy; Gemini 4 Argon costs less per question.
Which is cheaper, Claude Fable 5.1 or Gemini 4 Argon?
Gemini 4 Argon is cheaper: $0.0062 per question as billed, against $0.016. List prices: Claude Fable 5.1 $10 in / $50 out, Gemini 4 Argon $2 in / $10 out per million tokens.
Which is faster, Claude Fable 5.1 or Gemini 4 Argon?
Their output speed is similar: 70 and 69 tokens per second.
Which has the larger context window, Claude Fable 5.1 or Gemini 4 Argon?
Both accept about the same amount of context: 1M and 1M tokens.