Claude Opus 4.8 vs Mistral Medium 3.5 128B
Wins 6 of 7 areas
Coding · Agents · Reasoning · Facts · Images and charts · Long documents
Wins 1 of 7 areas
Following instructions
Claude Opus 4.8 is the stronger all-rounder.Mistral Medium 3.5 128B is cheaper and better at following instructions.
Scores updated · 23 tests both models report · How we compare
Where each one wins
Tests won in each of the seven 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.
- CodingWriting and fixing software50Claude Opus 4.85 of 5 tests
- AgentsCarrying out multi-step tasks on its own40Claude Opus 4.84 of 4 tests
- ReasoningHard problems that need careful thinking30Claude Opus 4.83 of 3 tests
- FactsGetting facts right instead of making them up20Claude Opus 4.82 of 2 tests
- Images and chartsUnderstanding pictures, charts and video10Claude Opus 4.81 of 1 test
- Long documentsFinding answers in very long texts10Claude Opus 4.81 of 1 test
- Following instructionsDoing exactly what it is asked01Mistral Medium 3.5 128B1 of 1 test
Images and charts, long documents and following instructions rest on a single test each.
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.
Mistral Medium 3.5 128B costs 70% 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 Opus 4.8 pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+42.3points ahead
- Finds hard-to-locate facts by browsing the webBrowseComp+35.7points ahead
- Very hard expert questions across many subjectsHumanity's Last Exam+34.9points ahead
Where Mistral Medium 3.5 128B pulls ahead
- Follows unfamiliar, precisely checkable instructionsIFBench+6.6points ahead
Every test, side by side
All 23 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Opus 4.8
- Terminal-Bench 2.1Claude Opus 4.8 by 3484.650.6+34
- LMArena · WebDevClaude Opus 4.8 by 291 rating points15561265+291 rating
- Terminal-Bench HardClaude Opus 4.8 by 2558.333.3+25
- SciCodeClaude Opus 4.8 by 14.254.440.2+14.2
- SWE-bench VerifiedClaude Opus 4.8 by 1188.677.6+11
AgentsClaude Opus 4.8
- BrowseCompClaude Opus 4.8 by 35.784.348.6+35.7
- GDPValClaude Opus 4.8 by 34.647.813.2+34.6
- Terminal-Bench 4.0Claude Opus 4.8 by 21.721.70+21.7
- τ-Bench V3 · BankingClaude Opus 4.8 by 19.134.215.1+19.1
ReasoningClaude Opus 4.8
- Humanity's Last ExamClaude Opus 4.8 by 34.948.713.8+34.9
- CritPtClaude Opus 4.8 by 20.920.90+20.9
- GPQA DiamondClaude Opus 4.8 by 17.29274.8+17.2
FactsClaude Opus 4.8
- AA-Omniscience · Non-hallucinationClaude Opus 4.8 by 42.360.718.4+42.3
- AA-Omniscience · AccuracyClaude Opus 4.8 by 24.148.824.7+24.1
Images and chartsClaude Opus 4.8
- LMArena · VisionClaude Opus 4.8 by 73 rating points12951222+73 rating
Following instructionsMistral Medium 3.5 128B
- IFBenchMistral Medium 3.5 128B by 6.662.268.8+6.6
Other results6 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 65.628.8-36.8+65.6
- AA Agentic IndexClaude Opus 4.8 by 33.242.69.4+33.2
- AA IntelligenceClaude Opus 4.8 by 27.641.814.2+27.6
- Artificial Analysis Coding IndexClaude Opus 4.8 by 27.474.346.9+27.4
- Finance Agent v2Claude Opus 4.8 by 21.853.932.1+21.8
- τ²-Bench Telecom (AA run)tie94.494.2tie
Questions people ask
Which is better, Claude Opus 4.8 or Mistral Medium 3.5 128B?
Claude Opus 4.8 wins six of the seven areas where both have results: coding, agents, reasoning, facts, images and charts and long documents. Mistral Medium 3.5 128B wins following instructions, and costs 70% less.
Which is better for coding?
Claude Opus 4.8. It wins 5 of the 5 coding tests both models report; Mistral Medium 3.5 128B wins none.
Which is cheaper?
Claude Opus 4.8 costs $5.00 per million input tokens and $25.00 per million output tokens; Mistral Medium 3.5 128B costs $1.50 and $7.50. That makes Mistral Medium 3.5 128B about 70% cheaper for the same work.
How do you compare the two?
We use the 23 benchmark tests both models have published scores on. The verdict counts the 17 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 6 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.