STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Gemini 3.8 Flash vs Muse Spark Open

Gemini 3.8 Flash leads Muse Spark Open by 3.8 points on StealthMark, 47.9 to 44.1. It leads on 6 of 9 benchmarks, including Foresight, and Muse Spark Open on 3, including Latch. Gemini 3.8 Flash scores higher on Newton's Mirror, with its largest category advantage in state at 600 ms.

See the difference ↘
All results ↗
All results ↗

Overall StealthMark

47.9/100Overall rank 20/53
44.1/100Overall rank 29/53

General Intelligence

43.9/100
42.6/100

Visual Intelligence

55.2/100
46.6/100

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

  • Muse Spark Open

Open or local

BENCHMARK BY BENCHMARK

Where each model leads

  • Gemini 3.8 Flash
  • Muse Spark Open
  • Other models
  • Median

DATASHEET

Specs and pricing

Gemini 3.8 Flash scores higher on StealthMark and is 13% cheaper per output token. Muse Spark Open runs 2.1× faster in our speed test. Both take about 1M tokens of context.

  • Gemini 3.8 Flash
  • Muse Spark Open
  • Other models
  • Median
PricePer 1M output tokens, input below
Gemini 3.8 Flash: $3.7513% cheaper$0.75 inputMuse Spark Open: $4.25$1.25 input
Context windowTokens per request, max output below
Gemini 3.8 Flash: 1MTied64K max outputMuse Spark Open: 1MTied1M max output
Output speedTokens per second, our measurement
Gemini 3.8 Flash: 170tokens/sMuse Spark Open: 3612.1× fastertokens/s
SizeTotal and active parameters
Gemini 3.8 Flash: Not disclosedMuse Spark Open: 816B42B active
Developer
GoogleMeta
Released
2 Sep 202615 Oct 2026
Origin
United StatesBoth
Input → output
Text, image, video, audio, PDF → textText, image, audio, video → text
Architecture
Not publishedSparse mixture-of-experts Transformer with perception encoders; 62 decoder layers, 256 experts with 8 selected per token, grouped-query attention and sliding-window/full-attention layers.

Full datasheets, every price and sourceGemini 3.8 Flash ↗Muse Spark Open ↗

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 3.8 Flash 45.4/100Rank 20/47

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

Muse Spark Open 29.4/100Rank 34/47

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

Points per level

LevelGemini 3.8 FlashMuse Spark Open
Level 1Second Thoughts
4 ptsOut of lives
4 ptsOut of lives
Level 2Pressure Pot
10 ptsSurvived
9 ptsOut of lives
Level 3Hide or Flight
11 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 3.8 Flash 72.9/100Rank 14/48

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

Muse Spark Open 75.7/100Rank 12/48

Cleared 5 of 5
Latch: complete playing field
Level 519.6 ptsTurn 32 / 40

Points per level

LevelGemini 3.8 FlashMuse Spark Open
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
9.8 ptsCleared
9.8 ptsCleared
Level 3Relay vault
18.8 ptsCleared
19.2 ptsCleared
Level 4Passing bay
17.8 ptsClearedFinished early · 1 beacon left
17.8 ptsClearedFinished early · 1 beacon left
Level 5Second thoughts
20.6 ptsCleared
19.6 ptsCleared

Newton's Mirror

Same task instructions

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

The judgment

Gemini 3.8 Flash

Crimson is carried well down the camera-facing surface, supporting its earlier interaction. The depiction remains highly simplified, with imperfect material rendering. Isolated wall and floor images and a few highlights provide scant reflective evidence; displaced first reflections, missing receding chains and absent nested sphere and emitter imagery leave the room's optical structure largely unsupported.

Muse Spark Open

The airborne black blob and deformed paint support the broad contact sequence, although cyan attachment and wheel-directed transport remain partial. The sphere and black blob have substantial framing errors. The dominant limitation is the largely absent mirror system: faint wall circles and isolated highlights provide little evidence of recursive room geometry or curved nested reflections. Oversized compact paint features and diffuse material treatment further limit credit.

Score breakdown

CategoryGemini 3.8 FlashMuse Spark Open
State at 600 ms22.5/2514.0/25
Camera and placement11.0/156.0/15
Reflections4.5/1208.0/120
Materials and scale7.0/103.5/10
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 3.8 Flash

The dominant four-point silhouette, luminous color progression, raised brows and enormous grin closely fulfill the brief. Attached, secondary limbs support the exuberant expression. Clean facial drawing and glossy eyes give strong character, while shallow depth, minimally articulated extremities and visible steps in the outer glow limit refinement.

Muse Spark Open

The rounded silhouette and asymmetric expression make an appealing baby elephant, supported by a quiet background and grounding shadow. The protective action remains difficult to read: forefeet cannot be confidently traced into a grip, and seed contact is crowded by fine lines. Controlled simple shapes provide charm, but limited anatomical clarity, shading and surface detail leave the execution uneven.

Score breakdown

CategoryGemini 3.8 FlashMuse Spark Open
Task & likeness8.0/105.0/10
Anatomy & construction6.0/104.5/10
Space & placement6.5/106.0/10
Light & reflections7.0/105.0/10
Purposeful detail5.0/106.0/10
Artistry & character3.5/105.0/10
Materials & effects5.0/105.0/10
Visual integrity6.5/106.5/10

Benchmark task

Gemini 3.8 Flash

A luminous star-shaped creature tests expressive features, a clear silhouette and smooth colour transitions.

Muse Spark Open

A small elephant protecting a delicate seed tests expressive anatomy, physical contact and contrasting organic materials.

Mona Lisa

Different task instructions

Precise visual recall and portrait reconstruction.

The judgment

Gemini 3.8 Flash

The dark clothing, overlapping hands and hazy landscape make the Mona Lisa reference recognizable. Replication is limited by the frontal, elongated face, heavy mouth and chin, and poorly resolved hands, wrists and forearm. Soft shading gives some volume, but muddy transitions, blunt landscape shapes and rigid facial modeling weaken the portrait’s expression and painterly character.

Muse Spark Open

A recognizable, orderly interpretation with clean major contours, connected body forms and modest facial shading. Wide eyes, frontal symmetry and schematic hands limit likeness and expression. Layered scenery establishes basic depth, but shallow arm overlaps, flat clothing and sparse fine detail keep the execution basic and uneven.

Score breakdown

CategoryGemini 3.8 FlashMuse Spark Open
Task & likeness3.0/103.0/10
Anatomy & construction2.0/103.0/10
Space & placement3.5/105.0/10
Light & reflections3.0/104.5/10
Purposeful detail5.0/104.0/10
Artistry & character3.0/103.0/10
Materials & effects5.0/104.0/10
Visual integrity1.0/106.0/10

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

Gemini 3.8 Flash

A vivid purple-and-gold sunset anchors an appealing beach composition with dolphins, birds, a turtle and playful accessories. Palm silhouettes frame the bright reflection effectively. Sparse animal anatomy, wirelike palm foliage, conspicuously regular reflection bands and limited surface texture keep the execution below exceptional.

Muse Spark Open

A coherent sunset beach with readable activities, balanced framing and controlled colour transitions. Small accessories add interest, but schematic anatomy, limited surface detail, weak directional shadows and a geometric reflection constrain its finish. Most shapes and overlaps remain clean.

Score breakdown

CategoryGemini 3.8 FlashMuse Spark Open
Task & likeness9.0/108.0/10
Anatomy & construction7.0/106.0/10
Space & placement7.0/106.5/10
Light & reflections8.0/105.5/10
Purposeful detail7.0/106.5/10
Artistry & character7.0/105.5/10
Materials & effects7.0/106.0/10
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

Gemini 3.8 Flash

This benchmark has not been assessed yet.

Muse Spark Open

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

Gemini 3.8 Flash

Expressive animals, a bold diagonal hull and sweeping spray create an appealing action scene. The raccoon's support on the dog's back is unclear, and the dog lacks a readable paw-to-control grip and connected steering assembly. Clean graphic shapes and lively accessories are stronger than the anatomical construction. Sunset illumination and reflections remain largely decorative.

Muse Spark Open

Expressive faces, distinct accessories and clean color separation make the scene appealing and recognizable. Character detail is stronger than the functional construction: steering contact, limb overlaps and seating remain ambiguous. The readable hull and lively spray establish motion, while limited directional shading and simplified surfaces constrain depth and physical coherence.

Score breakdown

CategoryGemini 3.8 FlashMuse Spark Open
Task & likeness7.0/104.0/10
Anatomy & construction6.0/103.0/10
Space & placement7.0/106.0/10
Light & reflections6.5/104.5/10
Purposeful detail7.5/107.0/10
Artistry & character7.5/103.5/10
Materials & effects7.5/105.0/10
Visual integrity7.5/105.0/10

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

Different task instructions

Subject construction and spatial relationships.

The judgment

Gemini 3.8 Flash

The pelican’s enormous bill, lively feathers and orange bicycle create a clear, appealing composition. Basket contents, spokes and facial details reward inspection. Both legs connect to the body, but foot-to-pedal placement and wing-to-handlebar contact are ambiguous. Bicycle mechanics and lighting remain schematic, limiting an otherwise polished illustration.

Muse Spark Open

A controlled, appealing cartoon with a recognizable pelican, expressive face and clean curved forms. Feather lines, spokes and bill shading provide useful complexity. Aligned wheels and a ground shadow establish placement, but uncertain pedal contacts and obscured mechanical connections weaken support and riding action. Lighting remains loosely coordinated with the sun.

Score breakdown

CategoryGemini 3.8 FlashMuse Spark Open
Task & likeness9.0/107.5/10
Anatomy & construction7.5/105.0/10
Space & placement7.5/106.0/10
Light & reflections7.0/105.0/10
Purposeful detail8.5/106.5/10
Artistry & character8.0/105.5/10
Materials & effects7.0/106.0/10
Visual integrity8.0/107.5/10

Benchmark task

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