STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Claude Opus 5.5 vs MiniMax M3.1 Flash

Claude Opus 5.5 leads MiniMax M3.1 Flash by 26.7 points on StealthMark, 72.6 to 45.9. It leads on 8 of 9 benchmarks, including both games, and MiniMax M3.1 Flash on 1. Claude Opus 5.5 scores higher on Newton's Mirror, with its largest category advantage in reflections.

See the difference ↘
All results ↗
All results ↗

Overall StealthMark

72.6/100Overall rank 2/53
45.9/100Overall rank 24/53

General Intelligence

71.3/100
35.8/100

Visual Intelligence

75.0/100
62.6/100

Reasoning efficiency

On every task, result quality and reasoning tokens are each compared with all measured models and weighed equally. Each dot is one model.

Single-step reasoning Result quality weighed against reasoning tokens on a single problem

Multi-step reasoning Result quality weighed against reasoning tokens across connected steps, as in agentic workflows

  • Claude Opus 5.5

BENCHMARK BY BENCHMARK

Where each model leads

  • Claude Opus 5.5
  • MiniMax M3.1 Flash
  • Other models
  • Median

DATASHEET

Specs and pricing

Both take about 1M tokens of context.

  • Claude Opus 5.5
  • MiniMax M3.1 Flash
  • Other models
  • Median
PricePer 1M output tokens, input below
Claude Opus 5.5: $20$4 inputMiniMax M3.1 Flash: No list price
Context windowTokens per request, max output below
Claude Opus 5.5: 1MTied128K max outputMiniMax M3.1 Flash: 1MTied
Output speedTokens per second, our measurement
Claude Opus 5.5: 166tokens/sMiniMax M3.1 Flash: Not measured
SizeTotal and active parameters
Claude Opus 5.5: Not disclosedMiniMax M3.1 Flash: 428B23B active
Developer
AnthropicMiniMax
Released
22 Sep 2026Not published
Origin
United StatesNot published
Input → output
Text, image → textText, image, video → text
Architecture
Not publishedMixture-of-Experts with MiniMax Sparse Attention and native multimodal encoder

Full datasheets, every price and sourceClaude Opus 5.5 ↗MiniMax M3.1 Flash ↗

Anticipating threats and planning ahead. Collect coins while avoiding ghosts. Ghosts move before the player each turn, and collisions cost a life. 3 levels in sequence, up to 66 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.

Claude Opus 5.5 66.3/100Rank 5/47

Survived 3 of 3
Foresight: complete playing field
Level 39 ptsTurn 20 / 20

MiniMax M3.1 Flash 30.7/100Rank 28/47

Survived 1 of 3
Foresight: complete playing field
Level 39 ptsTurn 20 / 20

Points per level

LevelClaude Opus 5.5MiniMax M3.1 Flash
Level 1Second Thoughts
27 ptsSurvived
6 ptsOut of lives
Level 2Pressure Pot
11 ptsSurvived
5 ptsOut of lives
Level 3Hide or Flight
9 ptsSurvived
9 ptsSurvived

Cooperative planning and learning from experience. Coordinate two robots to push numbered cores onto matching sockets. Pressure plates hold doors open; moving either robot uses one turn. 5 levels in sequence, up to 152 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.

Claude Opus 5.5 87.6/100Rank 1/48

Cleared 5 of 5
Latch: complete playing field
Level 520.6 ptsTurn 27 / 40

MiniMax M3.1 Flash 21.9/100Rank 38/48

Cleared 2 of 5
Latch: complete playing field
Level 517.2 ptsTurn 24 / 40

Points per level

LevelClaude Opus 5.5MiniMax M3.1 Flash
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
10.2 ptsClearedFinished early · 1 beacon left
8.6 ptsClearedFinished early · 1 beacon left
Level 3Relay vault
19.2 ptsCleared
5 ptsOut of turns
Level 4Passing bay
18.2 ptsClearedFinished early · 3 beacons left
4.4 ptsFinished early
Level 5Second thoughts
20.6 ptsCleared
17.2 ptsFinished early

Newton's Mirror

Same task instructions

Physics, perspective and recursive reflections, tested together. Explore the test ↗

The judgment

Claude Opus 5.5

Open lateral sightlines, first reflected silhouettes and near-field planar panel placement are convincing. Missing outer chains, truncated repetitions and absent nested spherical room and emitter imagery remain the main weaknesses.

MiniMax M3.1 Flash

The sphere placement, separate airborne black blob, recent cyan contact and elongated crimson aftermath support the required gross physical state. The reflection system remains severely incomplete: isolated side images, broad metallic bands and sparse light patches replace extensive mirror repetitions and curved nested imagery.

Score breakdown

CategoryClaude Opus 5.5MiniMax M3.1 Flash
State at 600 ms24.0/2520.0/25
Camera and placement15.0/1510.0/15
Reflections55.0/12024.0/120
Materials and scale9.0/108.0/10
Floor-damage reward0.0/100.0/10

Benchmark task

A spinning metal sphere and paint in a mirrored room test physical reasoning, perspective and consistency across repeated reflections.

Selfie

Different task instructions

Visual construction and creative interpretation.

The judgment

Claude Opus 5.5

The centered coral squid has a friendly, restrained expression and a balanced radial silhouette within a cream arch. Smooth curves and soft shading give it an appealing matte finish. The mantle is more elongated than compact, the upper arms are visually ambiguous, and the two hanging tentacles read somewhat like legs. Clean execution supports a strong stylized illustration.

MiniMax M3.1 Flash

The sculptural M, confident grin and miniature theatrical pose closely fulfill the brief. Controlled gradients and clean shapes give the character volume and appeal. Moderate drawing complexity, an apparently separated shoe and ambiguous grounding limit the finish.

Score breakdown

CategoryClaude Opus 5.5MiniMax M3.1 Flash
Task & likeness8.0/107.5/10
Anatomy & construction7.5/106.0/10
Space & placement8.0/107.0/10
Light & reflections7.5/106.0/10
Purposeful detail7.0/105.0/10
Artistry & character7.0/106.0/10
Materials & effects7.0/107.0/10
Visual integrity8.5/106.0/10

Benchmark task

Claude Opus 5.5

A coral squid with spreading arms tests connected anatomy, balanced composition and soft surface shading.

MiniMax M3.1 Flash

A small robot with an oversized angular head presents a glowing object. The scene tests character proportions, gesture and contrasting materials.

Mona Lisa

Different task instructions

Precise visual recall and portrait reconstruction.

The judgment

Claude Opus 5.5

The portrait preserves the recognizable composition, dark veil, folded hands and distant landscape. Replication is limited by the elongated face and neck, conspicuous eyes and simplified smile. Hands remain connected but their rounded fingers and wrists lack convincing anatomy. Restrained colors create cohesion; shallow modeling and pervasive mottling weaken volume and painterly subtlety.

MiniMax M3.1 Flash

A coherent decorative portrait combines layered hair, garment contours, linked trim and atmospheric scenery. These provide meaningful drawing complexity, but likeness remains limited by the frontal elongated face and altered clothing. Compressed hands, abrupt facial shading and cluttered local edges leave the portrait uneven.

Score breakdown

CategoryClaude Opus 5.5MiniMax M3.1 Flash
Task & likeness6.5/104.0/10
Anatomy & construction5.5/104.5/10
Space & placement6.5/105.5/10
Light & reflections6.5/104.5/10
Purposeful detail6.5/105.5/10
Artistry & character6.0/106.0/10
Materials & effects7.0/105.5/10
Visual integrity7.0/105.5/10

Benchmark task

An SVG interpretation of the Mona Lisa tests facial likeness, anatomy and the composition of a familiar portrait.

Beach

Different task instructions

Creativity, perspective and visual beauty.

The judgment

Claude Opus 5.5

A lively, well-composed beach illustration with rich sunset colors, recognizable animals and appealing accessories. The sun reflection establishes a strong central focus. Clean silhouettes and small details reward inspection, though simplified animal construction, uneven contact shadows and mostly flat materials limit depth and realism.

MiniMax M3.1 Flash

A controlled, detailed beach illustration with expressive animals, coherent depth and accomplished foliage and accessory drawing. Its warm palette and varied contours sustain visual interest. Simplified anatomy and object volumes limit physical conviction, while reflection streaks crossing dry-looking sand and generic shadows weaken the lighting.

Score breakdown

CategoryClaude Opus 5.5MiniMax M3.1 Flash
Task & likeness8.5/108.5/10
Anatomy & construction7.5/107.0/10
Space & placement7.0/107.5/10
Light & reflections7.5/106.0/10
Purposeful detail7.5/108.0/10
Artistry & character8.0/106.5/10
Materials & effects6.5/106.5/10
Visual integrity8.0/107.5/10

Benchmark task

A busy shoreline at sunset tests scene composition, animal forms and the relationship between light and water reflections.

Ground Truth

Same task instructions

Physical reasoning, light and visual reconstruction.

The judgment

Claude Opus 5.5

This benchmark has not been assessed yet.

MiniMax M3.1 Flash

This benchmark has not been assessed yet.

Benchmark task

A plank, computer mouse and blueberry in a steel room test physical stability, spatial relationships, materials and lighting.

Raccoon

Different task instructions

Scene composition and interacting subjects.

The judgment

Claude Opus 5.5

The masked raccoon clearly rides the dog's back, and the dog's forward paw reaches the steering grip. Expressive faces, vivid colors and sweeping wakes create an appealing illustration. Connected limbs remain schematic, as does the small steering assembly. The broad hull and flat foam weaken water contact; the glowing sun lacks a corresponding reflection or convincing cast shadows.

MiniMax M3.1 Flash

An expressive, coherent cartoon clearly demonstrates the requested riding and steering relationship. Layered animal shapes, readable vehicle depth and purposeful facial details support its drawing quality. Ambiguous grips, sparse cast shadows and simplified material responses limit physical precision.

Score breakdown

CategoryClaude Opus 5.5MiniMax M3.1 Flash
Task & likeness8.5/109.0/10
Anatomy & construction7.5/108.0/10
Space & placement7.5/108.0/10
Light & reflections6.0/106.0/10
Purposeful detail8.5/107.5/10
Artistry & character7.0/107.5/10
Materials & effects7.0/107.0/10
Visual integrity8.0/108.0/10

Benchmark task

A jet-ski scene pairs a canine driver with a raccoon passenger. It tests the placement and contact of interacting subjects, along with vehicle construction.

Pelican

Different task instructions

Subject construction and spatial relationships.

The judgment

Claude Opus 5.5

The recognizable pelican, orderly bicycle wheels and harmonious sunset create an appealing illustration. Both legs connect to the body and reach pedals; no clear detached or inverted parts appear. Steering contact and seating support are less convincing, while the drivetrain remains schematic. Crisp outlines give a clean finish, but limited shading and flat surfaces leave the scene with modest depth.

MiniMax M3.1 Flash

A controlled coastal illustration with a clear pelican silhouette, detailed wheels and accomplished feather and bill drawing. Continuous body construction and grounded wheels support the scene. Ambiguous leg, pedal and steering contacts weaken the riding mechanics; approximate directional lighting and simplified materials limit physical conviction.

Score breakdown

CategoryClaude Opus 5.5MiniMax M3.1 Flash
Task & likeness8.5/108.5/10
Anatomy & construction8.0/106.5/10
Space & placement7.0/108.0/10
Light & reflections6.0/107.0/10
Purposeful detail8.0/107.5/10
Artistry & character7.5/106.5/10
Materials & effects6.0/107.0/10
Visual integrity8.5/106.5/10

Benchmark task

A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.