ResearchLLM Verifications Leaderboard

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

Head to head · tested 27 Oct 2026

GPT-5.3-Codex vs Muse Spark Open: accuracy, speed and price

Similar accuracy; Muse Spark Open costs less per question.

OpenAIGPT-5.3-Codex82.5% score · #3$0.01 per question95 tok/sMetaMuse Spark Open77.5% score · #9$0.0045 per question220 tok/s

Verdict

Built from the measurements below

  • Accuracy is too close to call: GPT-5.3-Codex scored 82.5% and Muse Spark Open 77.5% on the same 80 questions, a gap within what chance alone could produce.
  • Muse Spark Open is 2.3× cheaper per question as billed ($0.0045 vs $0.01), reasoning tokens included.
  • Muse Spark Open generates text 2.3× faster: 220 tokens per second against 95.
  • Muse Spark Open starts answering sooner: 0.5 s to the first token, against 1.4 s for GPT-5.3-Codex.
  • Muse Spark Open accepts more context: 1M tokens against 400k.

Which should you choose?

Choose Muse Spark Open for the lower cost per correct answer ($0.0058 against $0.013), faster streaming, a quicker first token, open weights you can run yourself, a 1M-token context window and more hosts to choose from on OpenRouter (6 against 2). The widest subject gap is in science: GPT-5.3-Codex answered 28 of 30 correctly, Muse Spark Open 25 of 30. With so few questions per subject, treat this as a lead to test on your own prompts, not a result.

Accuracy gap +5.0 points (z = 0.79). 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

MeasureGPT-5.3-CodexMuse Spark OpenEdge
Verification scoreHigher is better82.5%77.5%Too close to call
Cost per questionLower is better$0.01$0.0045Muse Spark Open
Output speedHigher is better95220Muse Spark Open
Time to first tokenLower is better1.4 s0.5 sMuse Spark Open
End-to-end response timeLower is better5.2 s3.2 sMuse Spark Open
Tokens per questionLower is better699964GPT-5.3-Codex
Context windowHigher is better400k1MMuse Spark Open

Side by side

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

Every measure

GPT-5.3-Codex first, Muse Spark Open second

Verification scorehigher is better
GPT-5.3-Codex82.5%
Muse Spark Open77.5%
Cost per questionlower is better
GPT-5.3-Codex$0.01
Muse Spark Open$0.0045
Output speedhigher is better
GPT-5.3-Codex95
Muse Spark Open220
Time to first tokenlower is better
GPT-5.3-Codex1.4 s
Muse Spark Open0.5 s
End-to-end response timelower is better
GPT-5.3-Codex5.2 s
Muse Spark Open3.2 s
Tokens per questionlower is better
GPT-5.3-Codex699
Muse Spark Open964
Context windowhigher is better
GPT-5.3-Codex400k
Muse Spark Open1M

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 5.5GPT-6.1 SolGemini 4 ArgonGPT-5.4GPT-6 Lunagpt-oss-120bLlama 4 Maverick

Specifications and pricing

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

SpecificationGPT-5.3-CodexMuse Spark Open
CreatorOpenAIMeta
Released24 Feb 202615 Oct 2026
Weights—Open weights
ReasoningYesYes
Inputtext, image, filetext, image, video, file, audio
Outputtexttext
Context window400k tokens1M tokens
Knowledge cutoff——
List price in / out per 1M$1.75 / $14$1.25 / $4.25
Blended price per 1M (3:1)$4.81$2.00
Cheapest hostAzure · $1.75 / $14Makora · $1.25 / $4.25
Hosts on OpenRouter26
Last tested27 Oct 202626 Oct 2026

Compare any two models →

GPT-5.3-Codex vs Muse Spark Open: frequently asked questions

Is GPT-5.3-Codex better than Muse Spark Open?
On accuracy they are statistically tied: GPT-5.3-Codex scored 82.5% and Muse Spark Open 77.5% on the same 80 questions from open datasets. Similar accuracy; Muse Spark Open costs less per question.
Which is cheaper, GPT-5.3-Codex or Muse Spark Open?
Muse Spark Open is cheaper: $0.0045 per question as billed, against $0.01. List prices: GPT-5.3-Codex $1.75 in / $14 out, Muse Spark Open $1.25 in / $4.25 out per million tokens.
Which is faster, GPT-5.3-Codex or Muse Spark Open?
Muse Spark Open is faster at 220 output tokens per second, against 95. Time to first token: 1.4 s for GPT-5.3-Codex, 0.5 s for Muse Spark Open.
Which has the larger context window, GPT-5.3-Codex or Muse Spark Open?
Muse Spark Open, with 1M tokens against 400k.