STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Beam 1.0 501B A23B vs Muse Spark Open

Muse Spark Open leads Beam 1.0 501B A23B by 12.2 points on StealthMark, 44.1 to 31.9. It leads on 6 of 9 benchmarks, including Latch, and Beam 1.0 501B A23B on 3, including Foresight. Beam 1.0 501B A23B 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

31.9/100Overall rank 42/53
44.1/100Overall rank 29/53

General Intelligence

30.9/100
42.6/100

Visual Intelligence

33.8/100
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

Open modelApache 2.0

BENCHMARK BY BENCHMARK

Where each model leads

  • Beam 1.0 501B A23B
  • Muse Spark Open
  • Other models
  • Median

DATASHEET

Specs and pricing

Beam 1.0 501B A23B is 4.3× cheaper per output token and runs 2.7× faster in our speed test. Muse Spark Open scores higher on StealthMark. Both take about 1M tokens of context.

  • Beam 1.0 501B A23B
  • Muse Spark Open
  • Other models
  • Median
PricePer 1M output tokens, input below
Beam 1.0 501B A23B: $14.3× cheaper$0.25 inputMuse Spark Open: $4.25$1.25 input
Context windowTokens per request, max output below
Beam 1.0 501B A23B: 1MTied128K max outputMuse Spark Open: 1MTied1M max output
Output speedTokens per second, our measurement
Beam 1.0 501B A23B: 9722.7× fastertokens/sMuse Spark Open: 361tokens/s
SizeTotal and active parameters
Beam 1.0 501B A23B: 501B23.4B activeMuse Spark Open: 816B42B active
Developer
Reflection AIMeta
Released
16 Oct 202615 Oct 2026
Origin
United StatesBoth
Input → output
Text → textText, image, audio, video → text
Architecture
Sparse mixture-of-experts transformer; 52 layers (3 dense, 49 MoE), 256 experts with 8 selected per token; gated GQA and sliding-window attentionSparse 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 sourceBeam 1.0 501B A23B ↗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.

Beam 1.0 501B A23B 49.4/100Rank 18/47

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

LevelBeam 1.0 501B A23BMuse Spark Open
Level 1Second Thoughts
18 ptsOut of lives
4 ptsOut of lives
Level 2Pressure Pot
9 ptsOut of lives
9 ptsOut of lives
Level 3Hide or Flight
9 ptsSurvived
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.

Beam 1.0 501B A23B 37.3/100Rank 29/48

Cleared 2 of 5
Latch: complete playing field
Level 55 ptsTurn 30 / 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

LevelBeam 1.0 501B A23BMuse Spark Open
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
9.6 ptsCleared
9.8 ptsCleared
Level 3Relay vault
11.2 ptsFinished early
19.2 ptsCleared
Level 4Passing bay
3.6 ptsFinished early
17.8 ptsClearedFinished early · 1 beacon left
Level 5Second thoughts
5 ptsFinished early
19.6 ptsCleared

Newton's Mirror

Same task instructions

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

The judgment

Beam 1.0 501B A23B

Central object placement is fairly close, but the defining mirrored-room structure is missing. The paint colors suggest the required contact order without establishing their different interaction histories. The faint floor oval does not demonstrate valid reflection geometry, so it earns no reflection credit. Rounded volume and glossy paint provide limited material credit despite weak metallic finishes and oversized paint bodies.

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

CategoryBeam 1.0 501B A23BMuse Spark Open
State at 600 ms20.5/2514.0/25
Camera and placement11.5/156.0/15
Reflections2.0/1208.0/120
Materials and scale3.0/103.5/10
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

Beam 1.0 501B A23B

An appealing expression and warm palette support a coherent simple cartoon. The central polishing joke is not legible: the cloth is unresolved and the nose sits away from the fan. Pointed radial plates, uncertain limb attachments and weak ground contact limit construction, while restrained surface detail limits material richness.

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

CategoryBeam 1.0 501B A23BMuse Spark Open
Task & likeness4.0/105.0/10
Anatomy & construction3.5/104.5/10
Space & placement5.5/106.0/10
Light & reflections5.5/105.0/10
Purposeful detail4.5/106.0/10
Artistry & character4.0/105.0/10
Materials & effects4.5/105.0/10
Visual integrity7.0/106.5/10

Benchmark task

Beam 1.0 501B A23B

A golden pangolin polishes its oversized amber tail while its nose smudges the same scale. The scene tests expressive anatomy, physical contact and contrasting translucent, polished and soft materials.

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

Beam 1.0 501B A23B

The candidate shows a faint warm oval against an almost entirely black field. Minimal placement and smooth tonal variation are visible, but the portrait, anatomy, crossed hands and landscape remain unreadable. The saved comparisons provide no specific evidence supporting a change to the baseline categories.

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

CategoryBeam 1.0 501B A23BMuse Spark Open
Task & likeness0.0/103.0/10
Anatomy & construction0.0/103.0/10
Space & placement0.0/105.0/10
Light & reflections0.5/104.5/10
Purposeful detail0.0/104.0/10
Artistry & character0.0/103.0/10
Materials & effects0.0/104.0/10
Visual integrity0.0/106.0/10

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

Beam 1.0 501B A23B

A coherent, cheerful beach illustration fulfills the main subjects with clean shapes and a strong sunset focal point. Its basic geometric construction, ambiguous animal anatomy, shallow depth and schematic lighting limit its accomplishment. Decorative details provide interest without developing intricate forms or convincing physical surfaces.

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

CategoryBeam 1.0 501B A23BMuse Spark Open
Task & likeness7.0/108.0/10
Anatomy & construction5.0/106.0/10
Space & placement6.0/106.5/10
Light & reflections5.0/105.5/10
Purposeful detail5.5/106.5/10
Artistry & character4.0/105.5/10
Materials & effects5.0/106.0/10
Visual integrity5.0/108.0/10

Benchmark task

A busy shoreline at sunset tests scene composition, animal forms and the relationship between light and water reflections.

Ground Truth

Different task instructions

Physical reasoning, light and visual reconstruction.

The judgment

Beam 1.0 501B A23B

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

Beam 1.0 501B A23B

A cheerful, readable illustration with recognizable animals, expressive faces and useful accessories. Simple rounded construction limits complexity, while ambiguous steering attachments and weak hull-to-water contact reduce physical coherence. Lighting and surface effects establish the setting without convincing environmental interaction.

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

CategoryBeam 1.0 501B A23BMuse Spark Open
Task & likeness5.0/104.0/10
Anatomy & construction3.5/103.0/10
Space & placement5.5/106.0/10
Light & reflections4.0/104.5/10
Purposeful detail6.5/107.0/10
Artistry & character3.5/103.5/10
Materials & effects5.0/105.0/10
Visual integrity6.5/105.0/10

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

Beam 1.0 501B A23B

A cheerful, clearly readable pelican-and-bicycle illustration with clean contours and balanced composition. Simple geometric construction limits artistic complexity, while ambiguous neck and steering overlaps, merged pedal contacts and an incomplete drivetrain weaken physical coherence.

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

CategoryBeam 1.0 501B A23BMuse Spark Open
Task & likeness5.5/107.5/10
Anatomy & construction4.5/105.0/10
Space & placement5.0/106.0/10
Light & reflections4.0/105.0/10
Purposeful detail4.0/106.5/10
Artistry & character4.0/105.5/10
Materials & effects4.0/106.0/10
Visual integrity5.5/107.5/10

Benchmark task

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