STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Gemini 4 Argon vs GPT-5.6 Luna

Gemini 4 Argon leads GPT-5.6 Luna by 29.6 points on StealthMark, 67.4 to 37.8. It leads on all 9 benchmarks. Gemini 4 Argon scores higher on Newton's Mirror, with its largest category advantage in reflections.

See the difference ↘
All results ↗
All results ↗

Overall StealthMark

67.4/100Overall rank 5/53
37.8/100Overall rank 37/53

General Intelligence

63.6/100
30.4/100

Visual Intelligence

74.4/100
50.2/100

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

  • GPT-5.6 Luna

BENCHMARK BY BENCHMARK

Where each model leads

  • Gemini 4 Argon
  • GPT-5.6 Luna
  • Other models
  • Median

DATASHEET

Specs and pricing

Gemini 4 Argon scores higher on StealthMark. GPT-5.6 Luna is 8.3× cheaper per output token and runs 26% faster in our speed test. Both take about 1M tokens of context.

  • Gemini 4 Argon
  • GPT-5.6 Luna
  • Other models
  • Median
PricePer 1M output tokens, input below
Gemini 4 Argon: $10$2 inputGPT-5.6 Luna: $1.208.3× cheaper$0.20 input
Context windowTokens per request, max output below
Gemini 4 Argon: 1MTied1M max outputGPT-5.6 Luna: 1.05MTied128K max output
Output speedTokens per second, our measurement
Gemini 4 Argon: 144tokens/sGPT-5.6 Luna: 18126% fastertokens/s
Developer
GoogleOpenAI
Released
13 Oct 20269 Jul 2026
Origin
United StatesBoth
Input → output
Text, image, audio, video, PDF → textText, image → text
Architecture
Sparse mixture-of-experts (MoE) transformer with native multimodal inputsNot published

Full datasheets, every price and sourceGemini 4 Argon ↗GPT-5.6 Luna ↗

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.

Gemini 4 Argon 48.6/100Rank 19/47

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

GPT-5.6 Luna 25.1/100Rank 35/47

Survived 0 of 3
Foresight: complete playing field
Level 38 ptsTurn 15 / 20

Points per level

LevelGemini 4 ArgonGPT-5.6 Luna
Level 1Second Thoughts
26 ptsSurvived
4 ptsOut of lives
Level 2Pressure Pot
9 ptsOut of lives
6 ptsOut of lives
Level 3Hide or Flight
6 ptsOut of lives
8 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.

Gemini 4 Argon 82.6/100Rank 6/48

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

GPT-5.6 Luna 52.9/100Rank 21/48

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

Points per level

LevelGemini 4 ArgonGPT-5.6 Luna
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
9.8 ptsCleared
8.6 ptsClearedFinished early · 1 beacon left
Level 3Relay vault
19.2 ptsCleared
18 ptsCleared
Level 4Passing bay
18.2 ptsClearedFinished early · 3 beacons left
17 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

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.

GPT-5.6 Luna

The room enclosure has coherent symmetric perspective, with the overhead panel, sphere and black aligned centrally. The sphere and airborne black occupy substantially lower positions than the reference framing, inconsistent with the prescribed camera aim. The diagonal crimson streak does not establish the required surface transport. Faint wall sphere images provide limited mirrored correspondence, but the shallow floor image, missing receding chains, absent nested sphere imagery and sparse emitter mapping leave most reflection structure unsupported.

Score breakdown

CategoryGemini 4 ArgonGPT-5.6 Luna
State at 600 ms24.5/2515.0/25
Camera and placement14.5/154.0/15
Reflections50.5/1203.5/120
Materials and scale8.5/106.5/10
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

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.

GPT-5.6 Luna

Six pale, outward-facing heads and six rounded lobes make the knot recognizable. The central hexagonal opening remains clear. However, broad gray crossing panels flatten the weave, several inner joins resemble capped strips, and sparse oversized scale marks leave the bodies looking more like decorated ribbons than living snakes.

Score breakdown

CategoryGemini 4 ArgonGPT-5.6 Luna
Task & likeness7.0/107.5/10
Anatomy & construction6.5/106.0/10
Space & placement7.5/106.5/10
Light & reflections7.5/105.0/10
Purposeful detail8.0/105.5/10
Artistry & character7.0/106.0/10
Materials & effects7.0/105.0/10
Visual integrity7.5/106.0/10

Benchmark task

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.

GPT-5.6 Luna

A pale serpent woven into an interlocking knot tests connected anatomy, repeated structure and readable overlaps. Organic surface detail must work with the overall geometry.

Mona Lisa

Same task instructions

Precise visual recall and portrait reconstruction.

The judgment

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.

GPT-5.6 Luna

The central portrait, dark clothing, crossed hands and muted landscape clearly evoke Mona Lisa. Replication is limited by the elongated face, conspicuous eyes and simplified smile. Overlapping fingers have uncertain anatomy, while broad gradients and heavy outlines flatten the portrait. The composition and restrained palette remain coherent.

Score breakdown

CategoryGemini 4 ArgonGPT-5.6 Luna
Task & likeness6.5/103.5/10
Anatomy & construction6.5/103.5/10
Space & placement6.5/104.0/10
Light & reflections7.0/104.5/10
Purposeful detail6.0/104.0/10
Artistry & character6.5/104.0/10
Materials & effects7.0/103.5/10
Visual integrity7.0/104.5/10

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

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.

GPT-5.6 Luna

The warm sunset, palm silhouette and varied beach activities create an appealing, readable composition. Animals, birds and a broad sun reflection satisfy the brief. Drawing remains elementary: angular airborne sea animals lack splash or convincing motion, the crab's claws are awkwardly constructed, and repeated reflection bands suggest a stepped platform. Clean outlines and pleasant colors exceed the anatomical and spatial sophistication.

Score breakdown

CategoryGemini 4 ArgonGPT-5.6 Luna
Task & likeness9.0/107.5/10
Anatomy & construction7.5/104.0/10
Space & placement8.5/105.5/10
Light & reflections8.5/104.0/10
Purposeful detail9.0/106.5/10
Artistry & character8.0/103.5/10
Materials & effects8.0/104.0/10
Visual integrity8.0/103.5/10

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

Gemini 4 Argon

This benchmark has not been assessed yet.

GPT-5.6 Luna

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

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.

GPT-5.6 Luna

Expressive animals, a striped tail and clean outlines make the scene appealing and readable. The raccoon sits convincingly on the dog's back, but the overlapping steering paws are ambiguous and the control stem stops above the hull. Broad wake shapes suggest motion; the glowing sun lacks a corresponding water reflection.

Score breakdown

CategoryGemini 4 ArgonGPT-5.6 Luna
Task & likeness8.5/107.0/10
Anatomy & construction8.0/105.0/10
Space & placement7.5/106.5/10
Light & reflections7.5/106.0/10
Purposeful detail8.5/106.5/10
Artistry & character8.5/104.5/10
Materials & effects8.0/105.5/10
Visual integrity8.0/105.0/10

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

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.

GPT-5.6 Luna

A recognizable pelican cyclist with an expressive profile, balanced composition and controlled outlines. Head, neck and torso connect coherently. The bicycle wheels and frame are convincing, but overlapping feet obscure pedal contact, the drivetrain lacks a clear chain, and the wing's handlebar grip is schematic. Atmospheric color succeeds more strongly than directional lighting or material depth.

Score breakdown

CategoryGemini 4 ArgonGPT-5.6 Luna
Task & likeness9.0/108.5/10
Anatomy & construction8.5/105.5/10
Space & placement8.0/107.5/10
Light & reflections8.0/106.5/10
Purposeful detail8.5/106.5/10
Artistry & character8.5/105.5/10
Materials & effects8.5/107.0/10
Visual integrity8.5/106.5/10

Benchmark task

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