ResearchLLM Verifications Leaderboard

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

Head to head · tested 27 Oct 2026

Gemini 3.8 Flash vs GPT-5.3-Codex: accuracy, speed and price

Similar accuracy; Gemini 3.8 Flash costs less per question.

GoogleGemini 3.8 Flash82.5% score · #3$0.0037 per question142 tok/sOpenAIGPT-5.3-Codex82.5% score · #3$0.01 per question95 tok/s

Verdict

Built from the measurements below

  • Accuracy is too close to call: Gemini 3.8 Flash scored 82.5% and GPT-5.3-Codex 82.5% on the same 80 questions, a gap within what chance alone could produce.
  • Gemini 3.8 Flash is 2.8× cheaper per question as billed ($0.0037 vs $0.01), reasoning tokens included.
  • Gemini 3.8 Flash generates text 1.5× faster: 142 tokens per second against 95.
  • GPT-5.3-Codex starts answering sooner: 1.4 s to the first token, against 3.2 s for Gemini 3.8 Flash.
  • Gemini 3.8 Flash accepts more context: 1M tokens against 400k.

Which should you choose?

Choose Gemini 3.8 Flash for the lower cost per correct answer ($0.0045 against $0.013), faster streaming and a 1M-token context window. Choose GPT-5.3-Codex for a quicker first token. The widest subject gap is in law: Gemini 3.8 Flash answered 6 of 6 correctly, GPT-5.3-Codex 4 of 6. With so few questions per subject, treat this as a lead to test on your own prompts, not a result.

Accuracy gap +0.0 points (z = 0.00). 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

MeasureGemini 3.8 FlashGPT-5.3-CodexEdge
Verification scoreHigher is better82.5%82.5%Too close to call
Cost per questionLower is better$0.0037$0.01Gemini 3.8 Flash
Output speedHigher is better14295Gemini 3.8 Flash
Time to first tokenLower is better3.2 s1.4 sGPT-5.3-Codex
End-to-end response timeLower is better5.6 s5.2 sSimilar
Tokens per questionLower is better925699GPT-5.3-Codex
Context windowHigher is better1M400kGemini 3.8 Flash

Side by side

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

Every measure

Gemini 3.8 Flash first, GPT-5.3-Codex second

Verification scorehigher is better
Gemini 3.8 Flash82.5%
GPT-5.3-Codex82.5%
Cost per questionlower is better
Gemini 3.8 Flash$0.0037
GPT-5.3-Codex$0.01
Output speedhigher is better
Gemini 3.8 Flash142
GPT-5.3-Codex95
Time to first tokenlower is better
Gemini 3.8 Flash3.2 s
GPT-5.3-Codex1.4 s
End-to-end response timelower is better
Gemini 3.8 Flash5.6 s
GPT-5.3-Codex5.2 s
Tokens per questionlower is better
Gemini 3.8 Flash925
GPT-5.3-Codex699
Context windowhigher is better
Gemini 3.8 Flash1M
GPT-5.3-Codex400k

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 405BMuse WonderGrok 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-5.4GPT-6 Lunagpt-oss-120bLlama 4 Maverick

Specifications and pricing

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

SpecificationGemini 3.8 FlashGPT-5.3-Codex
CreatorGoogleOpenAI
Released2 Sept 202624 Feb 2026
Weights——
ReasoningYesYes
Inputtext, image, video, file, audiotext, image, file
Outputtexttext
Context window1M tokens400k tokens
Knowledge cutoff——
List price in / out per 1M$0.825 / $4.125$1.75 / $14
Blended price per 1M (3:1)$1.65$4.81
Cheapest hostGoogle AI Studio · $0.375 / $1.875Azure · $1.75 / $14
Hosts on OpenRouter22
Last tested25 Oct 202627 Oct 2026

Compare any two models →

Gemini 3.8 Flash vs GPT-5.3-Codex: frequently asked questions

Is Gemini 3.8 Flash better than GPT-5.3-Codex?
On accuracy they are statistically tied: Gemini 3.8 Flash scored 82.5% and GPT-5.3-Codex 82.5% on the same 80 questions from open datasets. Similar accuracy; Gemini 3.8 Flash costs less per question.
Which is cheaper, Gemini 3.8 Flash or GPT-5.3-Codex?
Gemini 3.8 Flash is cheaper: $0.0037 per question as billed, against $0.01. List prices: Gemini 3.8 Flash $0.825 in / $4.125 out, GPT-5.3-Codex $1.75 in / $14 out per million tokens.
Which is faster, Gemini 3.8 Flash or GPT-5.3-Codex?
Gemini 3.8 Flash is faster at 142 output tokens per second, against 95. Time to first token: 3.2 s for Gemini 3.8 Flash, 1.4 s for GPT-5.3-Codex.
Which has the larger context window, Gemini 3.8 Flash or GPT-5.3-Codex?
Gemini 3.8 Flash, with 1M tokens against 400k.