STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Claude Opus 5.5 vs Gemini 4 Argon

Claude Opus 5.5 leads Gemini 4 Argon by 5.2 points on StealthMark, 72.6 to 67.4. It leads on 5 of 9 benchmarks, including both games, and Gemini 4 Argon on 4. Claude Opus 5.5 scores higher on Ground Truth.

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All results ↗
All results ↗

Overall StealthMark

72.6/100Overall rank 2/53
67.4/100Overall rank 5/53

General Intelligence

71.3/100
63.6/100

Visual Intelligence

75.0/100
74.4/100

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
  • Gemini 4 Argon
  • Other models
  • Median

DATASHEET

Specs and pricing

Claude Opus 5.5 scores higher on StealthMark and runs 15% faster in our speed test. Gemini 4 Argon is 2× cheaper per output token. Both take about 1M tokens of context.

  • Claude Opus 5.5
  • Gemini 4 Argon
  • Other models
  • Median
PricePer 1M output tokens, input below
Claude Opus 5.5: $20$4 inputGemini 4 Argon: $102× cheaper$2 input
Context windowTokens per request, max output below
Claude Opus 5.5: 1MTied128K max outputGemini 4 Argon: 1MTied1M max output
Output speedTokens per second, our measurement
Claude Opus 5.5: 16615% fastertokens/sGemini 4 Argon: 144tokens/s
Developer
AnthropicGoogle
Released
22 Sep 202613 Oct 2026
Origin
United StatesBoth
Input → output
Text, image → textText, image, audio, video, PDF → text
Architecture
Not publishedSparse mixture-of-experts (MoE) transformer with native multimodal inputs

Full datasheets, every price and sourceClaude Opus 5.5 ↗Gemini 4 Argon ↗

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

Gemini 4 Argon 48.6/100Rank 19/47

Survived 1 of 3
Foresight: complete playing field
Level 36 ptsTurn 7 / 20

Points per level

LevelClaude Opus 5.5Gemini 4 Argon
Level 1Second Thoughts
27 ptsSurvived
26 ptsSurvived
Level 2Pressure Pot
11 ptsSurvived
9 ptsOut of lives
Level 3Hide or Flight
9 ptsSurvived
6 ptsOut of lives

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

Gemini 4 Argon 82.6/100Rank 6/48

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

Points per level

LevelClaude Opus 5.5Gemini 4 Argon
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
10.2 ptsClearedFinished early · 1 beacon left
9.8 ptsCleared
Level 3Relay vault
19.2 ptsCleared
19.2 ptsCleared
Level 4Passing bay
18.2 ptsClearedFinished early · 3 beacons left
18.2 ptsClearedFinished early · 3 beacons left
Level 5Second thoughts
20.6 ptsCleared
20.6 ptsCleared

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.

Gemini 4 Argon

The central sphere, separate airborne black blob, flattened cyan contact and displaced crimson aftermath support the principal camera and physical-state requirements. Open lateral lanes and initial reflection placements provide partial optical structure, but missing outer chains, sparse nested imagery and incomplete emitter mappings remain substantial limitations. The raised crimson mass also weakens paint-scale fidelity.

Score breakdown

CategoryClaude Opus 5.5Gemini 4 Argon
State at 600 ms24.0/2524.5/25
Camera and placement15.0/1514.5/15
Reflections55.0/12050.5/120
Materials and scale9.0/108.5/10
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.

Gemini 4 Argon

An appealing, controlled illustration with a distinctive buoyant silhouette, expressive comic face and rich luminous colour. The full composition and grounded slipper read clearly. The principal limitation is the crowded raised-foot interaction: paws, toes and lining overlap without making the bent leg or tight fit unmistakable.

Score breakdown

CategoryClaude Opus 5.5Gemini 4 Argon
Task & likeness8.0/107.0/10
Anatomy & construction7.5/106.5/10
Space & placement8.0/107.5/10
Light & reflections7.5/107.5/10
Purposeful detail7.0/108.0/10
Artistry & character7.0/107.0/10
Materials & effects7.0/107.0/10
Visual integrity8.5/107.5/10

Benchmark task

Claude Opus 5.5

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

Gemini 4 Argon

A luminous little dragon struggles with its bedtime slippers while a buoyant tail pulls it upward. The scene tests expressive anatomy, physical contact and the contrast between translucent forms and heavy objects.

Mona Lisa

Same 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.

Gemini 4 Argon

A coherent, moderately complex Mona Lisa reconstruction with substantial portrait volume, articulated clothing and landscape recession. Specific source features support replication beyond recognition alone. Altered facial likeness, uncertain crossed-hand anatomy and pervasive colored crackle keep the result uneven despite its developed shading and detail.

Score breakdown

CategoryClaude Opus 5.5Gemini 4 Argon
Task & likeness6.5/106.5/10
Anatomy & construction5.5/106.5/10
Space & placement6.5/106.5/10
Light & reflections6.5/107.0/10
Purposeful detail6.5/106.0/10
Artistry & character6.0/106.5/10
Materials & effects7.0/107.0/10
Visual integrity7.0/107.0/10

Benchmark task

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

Beach

Same 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.

Gemini 4 Argon

A strong decorative beach illustration with controlled color, intricate silhouettes and abundant playful detail. Connected dolphin forms and recognizable equipment support its construction, while the aligned sunset reflection anchors the scene. Compressed wave depth, ambiguous foreground support and uneven reflection specificity limit physical coherence. The saved comparisons support retaining the category assessments.

Score breakdown

CategoryClaude Opus 5.5Gemini 4 Argon
Task & likeness8.5/109.0/10
Anatomy & construction7.5/107.5/10
Space & placement7.0/108.5/10
Light & reflections7.5/108.5/10
Purposeful detail7.5/109.0/10
Artistry & character8.0/108.0/10
Materials & effects6.5/108.0/10
Visual integrity8.0/108.0/10

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.

Gemini 4 Argon

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

Same 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.

Gemini 4 Argon

An accomplished illustration with expressive characters, intricate spray and strong depth. Direct back seating, steering connections and hull-water contact are only partly demonstrated. Clean graphic execution and purposeful detail remain strengths, while shadows and reflections provide limited physical grounding.

Score breakdown

CategoryClaude Opus 5.5Gemini 4 Argon
Task & likeness8.5/108.5/10
Anatomy & construction7.5/108.0/10
Space & placement7.5/107.5/10
Light & reflections6.0/107.5/10
Purposeful detail8.5/108.5/10
Artistry & character7.0/108.5/10
Materials & effects7.0/108.0/10
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

Same 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.

Gemini 4 Argon

An expressive, detailed illustration with controlled gradients and coherent environmental depth. Continuous body contours and connected bicycle components establish competent construction. Steering grip and pedal engagement remain less explicit than the decorative details and wheel placement. These contact uncertainties limit action and placement credit without establishing broken anatomy.

Score breakdown

CategoryClaude Opus 5.5Gemini 4 Argon
Task & likeness8.5/109.0/10
Anatomy & construction8.0/108.5/10
Space & placement7.0/108.0/10
Light & reflections6.0/108.0/10
Purposeful detail8.0/108.5/10
Artistry & character7.5/108.5/10
Materials & effects6.0/108.5/10
Visual integrity8.5/108.5/10

Benchmark task

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