STEALTHMARK · HEAD TO HEAD

All comparisons ↗

GPT-6.1 Terra Low vs Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)

Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM) leads GPT-6.1 Terra Low by 21.3 points on StealthMark, 62.6 to 41.3. It leads on 8 of 9 benchmarks, including Foresight, and GPT-6.1 Terra Low on 1, including Latch. Union Alpha scores higher on Newton's Mirror, with its largest category advantage in reflections.

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All results ↗
Model guide ↗

Overall StealthMark

41.3/100Overall rank 35/55
62.6/100Overall rank 8/55

General Intelligence

34.3/100
58.7/100

Visual Intelligence

53.1/100
69.6/100

BENCHMARK BY BENCHMARK

Where each model leads

  • GPT-6.1 Terra Low
  • Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)
  • Other models
  • Median

DATASHEET

Specs and pricing

  • GPT-6.1 Terra Low
  • Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)
  • Other models
  • Median
Context windowTokens per request, max output below
GPT-6.1 Terra Low: Not publishedPareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM): 262K131K max output
Output speedTokens per second, our measurement
GPT-6.1 Terra Low: Not measuredPareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM): 26tokens/s
Developer
Not publishedCircuit & Chisel / Unbiased
Released
Not published20 Sep 2026
Origin
Not publishedUnited States
Input → output
Not publishedText, image → text

Full datasheets, every price and sourcePareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM) ↗

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.

GPT-6.1 Terra Low 36.1/100Rank 26/51

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

Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM) 78.7/100Rank 1/51

Survived 2 of 3
Foresight: complete playing field
Level 319 ptsTurn 20 / 20

Points per level

LevelGPT-6.1 Terra LowPareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)
Level 1Second Thoughts
4 ptsOut of lives
27 ptsSurvived
Level 2Pressure Pot
8 ptsOut of lives
12 ptsOut of lives
Level 3Hide or Flight
9 ptsSurvived
19 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.

GPT-6.1 Terra Low 62.4/100Rank 23/52

Cleared 4 of 5
Latch: complete playing field
Level 520.6 ptsTurn 27 / 40

Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM) 36.5/100Rank 34/52

Cleared 4 of 5
Latch: complete playing field
Level 519.4 ptsTurn 33 / 40

Points per level

LevelGPT-6.1 Terra LowPareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
9.2 ptsCleared
9.8 ptsCleared
Level 3Relay vault
18.8 ptsCleared
14.2 ptsClearedFinished early · 4 beacons left
Level 4Passing bay
10.2 ptsFinished early
9.2 ptsFinished early
Level 5Second thoughts
20.6 ptsCleared
19.4 ptsCleared

Newton's Mirror

Same task instructions

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

Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM) 52.0/100 Rank 7/55

Union Alpha: Newton's Mirror SVG benchmark

The judgment

GPT-6.1 Terra Low

Deformed colored paint and a separate airborne black body establish readable interaction history. Cyan has travelled too far, framing differs substantially, and the mirror system supplies only elementary bands and oval copies. Missing recursive geometry, nested spherical imagery and emitter mapping remain the dominant weaknesses.

Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)

Recognizable near-field sphere placement and bilateral convergence provide limited optical structure. Broad gray regions interrupt lateral sightlines and truncate side-floor images. Missing outer chains, absent nested sphere imagery and incomplete planar and curved emitter mappings dominate the reflection system.

Score breakdown

CategoryGPT-6.1 Terra LowPareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)
State at 600 ms22.0/2524.0/25
Camera and placement4.0/1513.5/15
Reflections10.0/12034.5/120
Materials and scale6.0/1010.0/10
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.

Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM) 76.5/100 Rank 7/55

Union Alpha: Selfie SVG benchmark

The judgment

GPT-6.1 Terra Low

Six attached outward-facing heads, delicate scales and soft ivory shading establish an orderly decorative motif. Separate paddle-shaped bodies replace the required interlocking loops and leave no enclosed central hexagon. Surface detail provides interest, but repeated simple forms, schematic faces and limited anatomical modeling constrain the result.

Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)

A strong futuristic emblem with clear hierarchy, controlled negative space and distinctive typography. Silver and gunmetal layers give the sweeping ribbons convincing graphic depth, while red accents remain restrained. Ambiguous concealed connections and occasionally abrupt highlight bands limit the construction and material realism.

Score breakdown

CategoryGPT-6.1 Terra LowPareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)
Task & likeness4.0/109.0/10
Anatomy & construction3.5/107.5/10
Space & placement4.5/108.5/10
Light & reflections5.5/107.5/10
Purposeful detail5.5/107.0/10
Artistry & character5.0/107.5/10
Materials & effects5.5/107.5/10
Visual integrity4.0/107.0/10

Benchmark task

GPT-6.1 Terra Low

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.

Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)

An interwoven metallic emblem tests ribbon geometry, overlapping forms and the appearance of reflective metal against a dark background.

Mona Lisa

Different task instructions

Precise visual recall and portrait reconstruction.

The judgment

GPT-6.1 Terra Low

A recognizable, coherent portrait with purposeful facial detail, warm local volume and layered scenery. The frontal pose, enlarged face, merged hands and shallow clothing construction substantially limit replication and drawing skill. The visible successes support retaining the current assessment.

Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)

The centered portrait, folded hands, dark clothing and hazy landscape clearly evoke the Mona Lisa. Muted colors and soft facial shading create a coherent illustration, but replication remains schematic: the face is broad, eyes outlined, smile simplified and overlapping fingers poorly resolved. Angular landscape shapes and flat fabric limit depth and painterly richness.

Score breakdown

CategoryGPT-6.1 Terra LowPareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)
Task & likeness5.0/106.5/10
Anatomy & construction4.5/105.0/10
Space & placement5.0/106.5/10
Light & reflections6.0/106.0/10
Purposeful detail5.0/105.5/10
Artistry & character5.5/106.5/10
Materials & effects5.0/105.0/10
Visual integrity6.0/107.0/10

Benchmark task

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

Beach

Different task instructions

Creativity, perspective and visual beauty.

The judgment

GPT-6.1 Terra Low

A coherent sunset scene demonstrates the beach, animals, birds and reflections. Flowing silhouettes, warm color transitions and intact attachments are its strongest properties. Simplified anatomy, the turtle's elevated viewing angle and symbolic surface effects constrain drawing complexity and physical depth.

Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)

A cohesive sunset palette, sweeping shoreline and playful animals make an appealing beach illustration. The sun’s reflection establishes a clear focal axis, balanced by the palm and umbrella. Clean silhouettes and small decorative features reward inspection, though simplified anatomy, repetitive reflection bars and generic oval shadows limit volume and naturalism.

Score breakdown

CategoryGPT-6.1 Terra LowPareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)
Task & likeness8.0/109.0/10
Anatomy & construction5.5/107.0/10
Space & placement5.5/108.0/10
Light & reflections6.5/107.0/10
Purposeful detail6.0/107.0/10
Artistry & character5.0/106.0/10
Materials & effects5.5/106.5/10
Visual integrity7.5/107.0/10

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.

Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM) 63.3/100 Rank 8/55

Union Alpha: Ground Truth SVG benchmark

The judgment

GPT-6.1 Terra Low

This benchmark has not been assessed yet.

Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)

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

GPT-6.1 Terra Low

Recognizable animals, a coherent craft and sweeping wake make an appealing cartoon. Basic limb construction, weakly demonstrated raccoon seating and limited shared perspective constrain the scene. Small identifying details work well, while lighting and materials remain broadly graphic.

Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)

Expressive animals, a readable riding arrangement and sweeping spray create an appealing cartoon. The raccoon sits convincingly on the dog's back, but the dog's paw does not clearly grip the handlebar, whose connection to the hull is unresolved. Flat lighting provides little volume or reflection. A dark rectangular strip interrupts the upper-right background.

Score breakdown

CategoryGPT-6.1 Terra LowPareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)
Task & likeness6.5/108.0/10
Anatomy & construction5.0/106.5/10
Space & placement5.5/107.5/10
Light & reflections4.5/105.5/10
Purposeful detail6.0/107.0/10
Artistry & character5.0/107.0/10
Materials & effects5.0/107.5/10
Visual integrity6.0/107.0/10

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

GPT-6.1 Terra Low

A coherent coastal illustration with a distinctive pelican, controlled contours and clearly organised bicycle wheels. Visible saddle support and shaped neck and wing contours earn credit beyond basic geometric construction. Rubbery legs, unresolved pedal contacts and absent steering contact limit the riding action. Lighting and materials remain restrained and spatially shallow.

Pareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)

The pelican is immediately recognizable, with an expressive face, convincing bill silhouette and appealing pastel composition. Both legs connect to feet, and the wing reaches the handlebar. Bicycle construction is less resolved: the far pedal lacks a clear crank connection and no chain is visible. Clean contours and orderly spokes support the illustration, while flat lighting and simplified surfaces limit depth.

Score breakdown

CategoryGPT-6.1 Terra LowPareto 26.9 (Union of GPT-6 Astra + DeepSeek + GLM)
Task & likeness7.0/108.0/10
Anatomy & construction5.5/106.0/10
Space & placement6.0/107.0/10
Light & reflections5.5/106.0/10
Purposeful detail6.5/106.0/10
Artistry & character6.0/106.0/10
Materials & effects6.0/106.0/10
Visual integrity6.0/108.5/10

Benchmark task

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