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 3.8 Flash: accuracy, speed and price

Similar accuracy; Gemini 3.8 Flash costs less per question.

AnthropicClaude Fable 5.181.2% score · #5$0.016 per question70 tok/sGoogleGemini 3.8 Flash82.5% score · #3$0.0037 per question142 tok/s

Verdict

Built from the measurements below

  • Accuracy is too close to call: Claude Fable 5.1 scored 81.2% and Gemini 3.8 Flash 82.5% on the same 80 questions, a gap within what chance alone could produce.
  • Gemini 3.8 Flash is 4.3× cheaper per question as billed ($0.0037 vs $0.016), reasoning tokens included.
  • Gemini 3.8 Flash generates text 2.0× faster: 142 tokens per second against 70.
  • Claude Fable 5.1 starts answering sooner: 2.1 s to the first token, against 3.2 s for Gemini 3.8 Flash.

Which should you choose?

Choose Claude Fable 5.1 for a quicker first token, shorter outputs (about 238 tokens per question against 925) and more hosts to choose from on OpenRouter (4 against 2). Choose Gemini 3.8 Flash for the lower cost per correct answer ($0.0045 against $0.02) and faster streaming.

Accuracy gap -1.2 points (z = -0.21). 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 3.8 FlashEdge
Verification scoreHigher is better81.2%82.5%Too close to call
Cost per questionLower is better$0.016$0.0037Gemini 3.8 Flash
Output speedHigher is better70142Gemini 3.8 Flash
Time to first tokenLower is better2.1 s3.2 sClaude Fable 5.1
End-to-end response timeLower is better11.0 s5.6 sGemini 3.8 Flash
Tokens per questionLower is better238925Claude 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 3.8 Flash second

Verification scorehigher is better
Claude Fable 5.181.2%
Gemini 3.8 Flash82.5%
Cost per questionlower is better
Claude Fable 5.1$0.016
Gemini 3.8 Flash$0.0037
Output speedhigher is better
Claude Fable 5.170
Gemini 3.8 Flash142
Time to first tokenlower is better
Claude Fable 5.12.1 s
Gemini 3.8 Flash3.2 s
End-to-end response timelower is better
Claude Fable 5.111.0 s
Gemini 3.8 Flash5.6 s
Tokens per questionlower is better
Claude Fable 5.1238
Gemini 3.8 Flash925
Context windowhigher is better
Claude Fable 5.11M
Gemini 3.8 Flash1M

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 5.5Gemini 3.8 FlashGPT-6.1 SolGPT-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 3.8 Flash
CreatorAnthropicGoogle
Released1 Sept 20262 Sept 2026
Weights——
ReasoningYesYes
Inputtext, image, filetext, image, video, file, audio
Outputtexttext
Context window1M tokens1M tokens
Knowledge cutoff——
List price in / out per 1M$10 / $50$0.825 / $4.125
Blended price per 1M (3:1)$20.00$1.65
Cheapest hostAzure · $10 / $50Google AI Studio · $0.375 / $1.875
Hosts on OpenRouter42
Last tested27 Oct 202625 Oct 2026

Compare any two models →

Claude Fable 5.1 vs Gemini 3.8 Flash: frequently asked questions

Is Claude Fable 5.1 better than Gemini 3.8 Flash?
On accuracy they are statistically tied: Claude Fable 5.1 scored 81.2% and Gemini 3.8 Flash 82.5% on the same 80 questions from open datasets. Similar accuracy; Gemini 3.8 Flash costs less per question.
Which is cheaper, Claude Fable 5.1 or Gemini 3.8 Flash?
Gemini 3.8 Flash is cheaper: $0.0037 per question as billed, against $0.016. List prices: Claude Fable 5.1 $10 in / $50 out, Gemini 3.8 Flash $0.825 in / $4.125 out per million tokens.
Which is faster, Claude Fable 5.1 or Gemini 3.8 Flash?
Gemini 3.8 Flash is faster at 142 output tokens per second, against 70. Time to first token: 2.1 s for Claude Fable 5.1, 3.2 s for Gemini 3.8 Flash.
Which has the larger context window, Claude Fable 5.1 or Gemini 3.8 Flash?
Both accept about the same amount of context: 1M and 1M tokens.