Claude Mythos 5.1 wins more areas, narrowly.GPT-5.6 Sol is cheaper.
Scores updated · 13 tests both models report · How we compare
Where each one wins
Tests won in each of the two 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.
Coding 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.
GPT-5.6 Sol costs 60% less for the same work.
The biggest differences
The tests each model wins by the widest margin, up to three each. Scores are out of 100.
Where Claude Mythos 5.1 pulls ahead
- Long, multi-file coding tasks in real codebasesSWE-bench Pro+16.6points ahead
- Very hard expert questions across many subjectsHumanity's Last Exam+11.4points ahead
Where GPT-5.6 Sol pulls ahead
- Abstract visual puzzles that people can solveARC-AGI-2+2.5points ahead
Every test, side by side
All 13 tests both models report. The winning score is in its model's colour; marks a score checked independently.
ReasoningEven
- Humanity's Last ExamClaude Mythos 5.1 by 11.460.949.5+11.4
- ARC-AGI-2GPT-5.6 Sol by 2.59092.5+2.5
Other results10 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.
- Program BenchClaude Mythos 5.1 by 62.687.625+62.6
- Terminal-Bench-Science 0.1Claude Mythos 5.1 by 30.252.622.4+30.2
- Terminal-Bench 4.0Claude Mythos 5.1 by 23.660.937.3+23.6
- OSWorld 2.0 (partial)Claude Mythos 5.1 by 15.377.962.6+15.3
- GDPval-AA v2Claude Mythos 5.1 by 142 rating points18531711+142 rating
- ProteinGym HardClaude Mythos 5.1 by 13.849.335.5+13.8
- DeepSWE 1.1GPT-5.6 Sol by 5.667.473+5.6
- HealthBench ProfessionalClaude Mythos 5.1 by 1.662.160.5+1.6
- ARC-AGI-1Claude Mythos 5.1 by 197.596.5+1
- HLE (with tools)tie6564.5tie
Questions people ask
Which is better, Claude Mythos 5.1 or GPT-5.6 Sol?
Claude Mythos 5.1 wins one of the two areas where both have results: coding. GPT-5.6 Sol wins none, but costs 60% less. They are level on reasoning.
Which is better for coding?
Claude Mythos 5.1. It wins the one coding test both models report.
Which is cheaper?
Claude Mythos 5.1 costs $10.00 per million input tokens and $50.00 per million output tokens; GPT-5.6 Sol costs $4.00 and $20.00. That makes GPT-5.6 Sol about 60% cheaper for the same work.
How do you compare the two?
We use the 13 benchmark tests both models have published scores on. The verdict counts the 3 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 10 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.