STEALTHMARK · HEAD TO HEAD

All comparisons ↗

GPT-5.6 Sol vs MiMo-V2.6-Pro

GPT-5.6 Sol leads MiMo-V2.6-Pro by 6.2 points on StealthMark, 54.1 to 47.9. It leads on 7 of 9 benchmarks, including both games, and MiMo-V2.6-Pro on 2. MiMo-V2.6-Pro scores higher on Newton's Mirror, with its largest category advantage in reflections.

See the difference ↘
All results ↗
All results ↗

Overall StealthMark

54.1/100Overall rank 12/53
47.9/100Overall rank 21/53

General Intelligence

51.9/100
44.3/100

Visual Intelligence

58.2/100
54.3/100

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

Open or local

Open modelMIT

BENCHMARK BY BENCHMARK

Where each model leads

  • GPT-5.6 Sol
  • MiMo-V2.6-Pro
  • Other models
  • Median

DATASHEET

Specs and pricing

GPT-5.6 Sol scores higher on StealthMark. MiMo-V2.6-Pro is 23× cheaper per output token and runs 42% faster in our speed test. Both take about 1.05M tokens of context.

  • GPT-5.6 Sol
  • MiMo-V2.6-Pro
  • Other models
  • Median
PricePer 1M output tokens, input below
GPT-5.6 Sol: $20$4 inputMiMo-V2.6-Pro: $0.8723× cheaper$0.43 input
Context windowTokens per request, max output below
GPT-5.6 Sol: 1.05MTied128K max outputMiMo-V2.6-Pro: 1MTied128K max output
Output speedTokens per second, our measurement
GPT-5.6 Sol: 81tokens/sMiMo-V2.6-Pro: 11642% fastertokens/s
SizeTotal and active parameters
GPT-5.6 Sol: Not disclosedMiMo-V2.6-Pro: 1.02T42B active
Developer
OpenAIXiaomi
Released
9 Jul 202621 Sep 2026
Origin
United StatesChina
Input → output
Text, image → textText, image, video, audio → text
Architecture
Not publishedSparse Mixture-of-Experts; OpenRouter maps the route to the released Pro-RL checkpoint. The UltraSpeed edition is a separate route

Full datasheets, every price and sourceGPT-5.6 Sol ↗MiMo-V2.6-Pro ↗

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-5.6 Sol 62.9/100Rank 8/47

Survived 1 of 3
Foresight: complete playing field
Level 311 ptsTurn 17 / 20

MiMo-V2.6-Pro 54.6/100Rank 13/47

Survived 1 of 3
Foresight: complete playing field
Level 319 ptsTurn 20 / 20

Points per level

LevelGPT-5.6 SolMiMo-V2.6-Pro
Level 1Second Thoughts
27 ptsSurvived
4 ptsOut of lives
Level 2Pressure Pot
10 ptsOut of lives
9 ptsOut of lives
Level 3Hide or Flight
11 ptsOut of lives
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-5.6 Sol 83.6/100Rank 5/48

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

MiMo-V2.6-Pro 52.6/100Rank 22/48

Cleared 5 of 5
Latch: complete playing field
Level 520.4 ptsTurn 28 / 40

Points per level

LevelGPT-5.6 SolMiMo-V2.6-Pro
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
10.2 ptsClearedFinished early · 1 beacon left
9 ptsClearedFinished early · 1 beacon left
Level 3Relay vault
18.8 ptsCleared
17.2 ptsClearedFinished early · 1 beacon left
Level 4Passing bay
18.2 ptsClearedFinished early · 3 beacons left
16 ptsClearedFinished early · 3 beacons left
Level 5Second thoughts
20.6 ptsCleared
20.4 ptsCleared

Newton's Mirror

Same task instructions

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

The judgment

GPT-5.6 Sol

The central sphere and paint ordering are supported, but a frontal, centrally converging chamber replaces the required corner perspective. The first wall and floor images have incorrect placement and scale relationships. Sparse reflection cues remain, while continuous outer chains, open lateral sightlines, dense planar light sequences and curved nested spherical imagery are largely missing.

MiMo-V2.6-Pro

The main framing and visible paint-contact story are well supported. Major optical omissions dominate the result: sparse repetitions, undersized first images, missing outer chains and absent curved nested imagery prevent a coherent mirror-room system. The metallic forms remain convincing in volume but have a soft illustrative finish.

Score breakdown

CategoryGPT-5.6 SolMiMo-V2.6-Pro
State at 600 ms23.0/2523.0/25
Camera and placement6.0/1512.0/15
Reflections11.0/12019.0/120
Materials and scale7.5/107.5/10
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

GPT-5.6 Sol

Six evenly spaced lobes, outward-facing heads and a clear central hexagon establish the requested knot. The ivory silhouette is controlled, but broad crossing bands resemble rigid strips, shading provides limited muscular volume, and repetitive scale lines extend across black loop openings. Small oval heads have readable eyes and mouths but limited anatomical character or moist surface detail.

MiMo-V2.6-Pro

An appealing rabbit with balanced framing, expressive eyes and purposeful costume accents. Simple frontal construction limits anatomical and spatial accomplishment. The orange orb provides an effective luminous focal point, but unreadable wrist connections weaken the requested gestures and prevent stronger integrity credit.

Score breakdown

CategoryGPT-5.6 SolMiMo-V2.6-Pro
Task & likeness7.5/106.5/10
Anatomy & construction6.0/105.0/10
Space & placement7.0/105.5/10
Light & reflections5.0/106.5/10
Purposeful detail6.0/106.5/10
Artistry & character6.5/105.0/10
Materials & effects4.5/106.5/10
Visual integrity6.0/106.0/10

Benchmark task

GPT-5.6 Sol

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.

MiMo-V2.6-Pro

A small rabbit in an explorer outfit floats with a luminous orb. The scene tests character anatomy, pose and the placement of geometric forms around it.

Mona Lisa

Different task instructions

Precise visual recall and portrait reconstruction.

The judgment

GPT-5.6 Sol

The crossed hands, dark dress and winding landscape establish the Mona Lisa composition. Replication is limited by enlarged eyes, an elongated face and a more frontal pose. Broad gradients suggest volume, but outlined features and flattened, overlapping fingers weaken the portrait. The frame and restrained palette unify the image; visible grain adds texture without convincing painterly transitions.

MiMo-V2.6-Pro

The portrait is recognizable through its dark silhouette, slight smile and muted landscape, but replication is weak. A frontal, oversized head and symmetric torso replace the reference's turned seated pose; angular, separated hands omit its central gesture. Smooth shading maintains coherence while anatomical detail, depth and material rendering remain basic.

Score breakdown

CategoryGPT-5.6 SolMiMo-V2.6-Pro
Task & likeness4.5/103.5/10
Anatomy & construction4.0/103.5/10
Space & placement5.5/104.0/10
Light & reflections5.0/105.0/10
Purposeful detail5.0/103.0/10
Artistry & character4.5/104.0/10
Materials & effects5.5/104.0/10
Visual integrity6.5/106.0/10

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

GPT-5.6 Sol

The purple-to-gold sunset, framing palms and varied beach activities create an appealing, coherent illustration. The sun’s reflection establishes a clear focal path. Figures and animals are recognizable but geometrically simplified; airborne dolphins lack convincing splashes, and the boat reflection is schematic. Clean silhouettes and playful details succeed more strongly than anatomical depth or material realism.

MiMo-V2.6-Pro

A readable sunset beach with clear requested subjects, appealing framing and purposeful accessories. Schematic anatomy, flattened foreground objects, repetitive water highlights and sparse directional shadows limit construction and physical depth. The kite's unresolved anchor also constrains integrity.

Score breakdown

CategoryGPT-5.6 SolMiMo-V2.6-Pro
Task & likeness8.5/108.5/10
Anatomy & construction6.0/105.0/10
Space & placement7.0/106.0/10
Light & reflections6.5/106.5/10
Purposeful detail7.0/106.5/10
Artistry & character6.5/105.0/10
Materials & effects6.5/106.0/10
Visual integrity7.0/106.0/10

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

GPT-5.6 Sol

This benchmark has not been assessed yet.

MiMo-V2.6-Pro

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

GPT-5.6 Sol

Expressive faces, bold silhouettes and layered waves make an appealing cartoon. The raccoon sits convincingly behind the dog's shoulders, and the dog's forward paw reaches the steering grip. Steering construction and seated support remain somewhat ambiguous. The glowing sunset lacks a corresponding warm reflection or consistent illumination on the riders.

MiMo-V2.6-Pro

A coherent, cheerful cartoon with recognizable animals, readable steering contact and useful small details. The dog's orientation follows the craft more successfully than a wholly frontal pose would. Simple anatomy, weak raccoon grip and compressed seating contacts still limit physical credibility. Gradients and spray provide polish without resolving complex construction.

Score breakdown

CategoryGPT-5.6 SolMiMo-V2.6-Pro
Task & likeness6.5/107.0/10
Anatomy & construction5.0/105.0/10
Space & placement6.5/105.5/10
Light & reflections6.5/105.5/10
Purposeful detail7.5/106.0/10
Artistry & character5.0/104.0/10
Materials & effects7.0/105.5/10
Visual integrity5.0/104.5/10

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

GPT-5.6 Sol

The expressive pelican and balanced coastal composition remain appealing, but a sky-colored slit between the neck contours above the wing leaves the central anatomy incoherent. This visible construction and layering defect prevents a clean-integrity assessment. Clustered feet lack clear pedal contacts and the chain routing is schematic; lighting and water reflections remain graphic.

MiMo-V2.6-Pro

The distinctive bill, continuous silhouette and detailed wheels establish a readable pelican cyclist. Shaped feathers and soft shading add character, but jointless legs, crowded pedal contacts, absent steering contact and loosely directional lighting limit the construction. The comparisons support retaining the baseline category scores.

Score breakdown

CategoryGPT-5.6 SolMiMo-V2.6-Pro
Task & likeness8.5/106.5/10
Anatomy & construction5.0/105.0/10
Space & placement7.5/106.0/10
Light & reflections7.5/105.5/10
Purposeful detail8.0/106.0/10
Artistry & character6.5/106.0/10
Materials & effects7.0/105.5/10
Visual integrity4.5/106.0/10

Benchmark task

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