Claude Opus 4.8 wins more areas, narrowly.Muse Spark Open is cheaper and better at facts.
Scores updated · 15 tests both models report · How we compare
Where each one wins
Tests won in each of the six areas where both have results. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
- ReasoningHard problems that need careful thinking30Claude Opus 4.83 of 3 tests
- AgentsCarrying out multi-step tasks on its own20Claude Opus 4.82 of 2 tests
- MathCompetition and research-level math20Claude Opus 4.82 of 2 tests
- FactsGetting facts right instead of making them up12Muse Spark Open2 of 3 tests
- CodingWriting and fixing software11Even1 each
- Long documentsFinding answers in very long texts00Even0 each · 1 tie
Long documents rests on a single test.
What it costs
Prices per million tokens, roughly 750,000 words. The bars show the cost of a million tokens read plus a million written.
Muse Spark Open costs 82% less for the same work.
The biggest differences
The three tests each model wins by the widest margin. Scores are out of 100.
Where Claude Opus 4.8 pulls ahead
- Extremely hard research-level math problemsFrontierMath Tier 4+24.4points ahead
- Complex command-line tasks across many fieldsTerminal-Bench 4.0+13.6points ahead
- Unpublished advanced math problemsFrontierMath Tiers 1-3 (v2)+10.2points ahead
Where Muse Spark Open pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+15.2points ahead
- Code for real scientific research problemsSciCode+4points ahead
- Short factual questions, answered correctlySimpleQA Verified+3.6points ahead
Every test, side by side
All 15 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingEven
- Terminal-Bench 2.1Claude Opus 4.8 by 8.284.676.4+8.2
- SciCodeMuse Spark Open by 454.458.4+4
AgentsClaude Opus 4.8
- Terminal-Bench 4.0Claude Opus 4.8 by 13.621.78.1+13.6
- GDPValClaude Opus 4.8 by 2.647.745.1+2.6
ReasoningClaude Opus 4.8
- CritPtClaude Opus 4.8 by 620.914.9+6
- Humanity's Last ExamClaude Opus 4.8 by 4.848.743.9+4.8
- GPQA DiamondClaude Opus 4.8 by 39289+3
FactsMuse Spark Open
- AA-Omniscience · Non-hallucinationMuse Spark Open by 15.260.775.9+15.2
- AA-Omniscience · AccuracyClaude Opus 4.8 by 9.548.839.3+9.5
- SimpleQA VerifiedMuse Spark Open by 3.65356.6+3.6
MathClaude Opus 4.8
- FrontierMath Tier 4Claude Opus 4.8 by 24.456.131.7+24.4
- FrontierMath Tiers 1-3 (v2)Claude Opus 4.8 by 10.28069.8+10.2
Other results2 tests, not counted
Tests outside the eight areas. They are not counted above: several are summary scores built from other tests, or the same test under another name.
- AA-OmniscienceClaude Opus 4.8 by 4.128.824.6+4.1
- AA IntelligenceClaude Opus 4.8 by 2.941.838.9+2.9
Questions people ask
Which is better, Claude Opus 4.8 or Muse Spark Open?
Claude Opus 4.8 wins three of the six areas where both have results: agents, reasoning and math. Muse Spark Open wins facts, and costs 82% less. They are level on coding and long documents.
Which is better for coding?
Neither. They win 1 coding test each of the 2 both models report.
Which is cheaper?
Claude Opus 4.8 costs $5.00 per million input tokens and $25.00 per million output tokens; Muse Spark Open costs $1.25 and $4.25. That makes Muse Spark Open about 82% cheaper for the same work.
How do you compare the two?
We use the 15 benchmark tests both models have published scores on. The verdict counts the 13 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 2 are listed but not counted, because several are summary scores or repeat a test. Each score is the one shown on the model's own page.