STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Beam 1.0 501B A23B vs Claude Opus 5.5

Claude Opus 5.5 leads Beam 1.0 501B A23B by 40.7 points on StealthMark, 72.6 to 31.9. It leads on all 9 benchmarks. Claude Opus 5.5 scores higher on Newton's Mirror, with its largest category advantage in reflections.

See the difference ↘
All results ↗
All results ↗

Overall StealthMark

31.9/100Overall rank 42/53
72.6/100Overall rank 2/53

General Intelligence

30.9/100
71.3/100

Visual Intelligence

33.8/100
75.0/100

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

  • Claude Opus 5.5

Open or local

Open modelApache 2.0

BENCHMARK BY BENCHMARK

Where each model leads

  • Beam 1.0 501B A23B
  • Claude Opus 5.5
  • Other models
  • Median

DATASHEET

Specs and pricing

Beam 1.0 501B A23B is 20× cheaper per output token and runs 5.9× faster in our speed test. Claude Opus 5.5 scores higher on StealthMark. Both take about 1M tokens of context.

  • Beam 1.0 501B A23B
  • Claude Opus 5.5
  • Other models
  • Median
PricePer 1M output tokens, input below
Beam 1.0 501B A23B: $120× cheaper$0.25 inputClaude Opus 5.5: $20$4 input
Context windowTokens per request, max output below
Beam 1.0 501B A23B: 1MTied128K max outputClaude Opus 5.5: 1MTied128K max output
Output speedTokens per second, our measurement
Beam 1.0 501B A23B: 9725.9× fastertokens/sClaude Opus 5.5: 166tokens/s
SizeTotal and active parameters
Beam 1.0 501B A23B: 501B23.4B activeClaude Opus 5.5: Not disclosed
Developer
Reflection AIAnthropic
Released
16 Oct 202622 Sep 2026
Origin
United StatesBoth
Input → output
Text → textText, image → 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 attentionNot published

Full datasheets, every price and sourceBeam 1.0 501B A23B ↗Claude Opus 5.5 ↗

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

Claude Opus 5.5 66.3/100Rank 5/47

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

Points per level

LevelBeam 1.0 501B A23BClaude Opus 5.5
Level 1Second Thoughts
18 ptsOut of lives
27 ptsSurvived
Level 2Pressure Pot
9 ptsOut of lives
11 ptsSurvived
Level 3Hide or Flight
9 ptsSurvived
9 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.

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

Cleared 2 of 5
Latch: complete playing field
Level 55 ptsTurn 30 / 40

Claude Opus 5.5 87.6/100Rank 1/48

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

Points per level

LevelBeam 1.0 501B A23BClaude Opus 5.5
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
9.6 ptsCleared
10.2 ptsClearedFinished early · 1 beacon left
Level 3Relay vault
11.2 ptsFinished early
19.2 ptsCleared
Level 4Passing bay
3.6 ptsFinished early
18.2 ptsClearedFinished early · 3 beacons left
Level 5Second thoughts
5 ptsFinished early
20.6 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.

Claude Opus 5.5

Open lateral sightlines, first reflected silhouettes and near-field planar panel placement are convincing. Missing outer chains, truncated repetitions and absent nested spherical room and emitter imagery remain the main weaknesses.

Score breakdown

CategoryBeam 1.0 501B A23BClaude Opus 5.5
State at 600 ms20.5/2524.0/25
Camera and placement11.5/1515.0/15
Reflections2.0/12055.0/120
Materials and scale3.0/109.0/10
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.

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.

Claude Opus 5.5

The centered coral squid has a friendly, restrained expression and a balanced radial silhouette within a cream arch. Smooth curves and soft shading give it an appealing matte finish. The mantle is more elongated than compact, the upper arms are visually ambiguous, and the two hanging tentacles read somewhat like legs. Clean execution supports a strong stylized illustration.

Score breakdown

CategoryBeam 1.0 501B A23BClaude Opus 5.5
Task & likeness4.0/108.0/10
Anatomy & construction3.5/107.5/10
Space & placement5.5/108.0/10
Light & reflections5.5/107.5/10
Purposeful detail4.5/107.0/10
Artistry & character4.0/107.0/10
Materials & effects4.5/107.0/10
Visual integrity7.0/108.5/10

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.

Claude Opus 5.5

A coral squid with spreading arms tests connected anatomy, balanced composition and soft surface shading.

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.

Claude Opus 5.5

The portrait preserves the recognizable composition, dark veil, folded hands and distant landscape. Replication is limited by the elongated face and neck, conspicuous eyes and simplified smile. Hands remain connected but their rounded fingers and wrists lack convincing anatomy. Restrained colors create cohesion; shallow modeling and pervasive mottling weaken volume and painterly subtlety.

Score breakdown

CategoryBeam 1.0 501B A23BClaude Opus 5.5
Task & likeness0.0/106.5/10
Anatomy & construction0.0/105.5/10
Space & placement0.0/106.5/10
Light & reflections0.5/106.5/10
Purposeful detail0.0/106.5/10
Artistry & character0.0/106.0/10
Materials & effects0.0/107.0/10
Visual integrity0.0/107.0/10

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

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.

Claude Opus 5.5

A lively, well-composed beach illustration with rich sunset colors, recognizable animals and appealing accessories. The sun reflection establishes a strong central focus. Clean silhouettes and small details reward inspection, though simplified animal construction, uneven contact shadows and mostly flat materials limit depth and realism.

Score breakdown

CategoryBeam 1.0 501B A23BClaude Opus 5.5
Task & likeness7.0/108.5/10
Anatomy & construction5.0/107.5/10
Space & placement6.0/107.0/10
Light & reflections5.0/107.5/10
Purposeful detail5.5/107.5/10
Artistry & character4.0/108.0/10
Materials & effects5.0/106.5/10
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.

Claude Opus 5.5

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.

Claude Opus 5.5

The masked raccoon clearly rides the dog's back, and the dog's forward paw reaches the steering grip. Expressive faces, vivid colors and sweeping wakes create an appealing illustration. Connected limbs remain schematic, as does the small steering assembly. The broad hull and flat foam weaken water contact; the glowing sun lacks a corresponding reflection or convincing cast shadows.

Score breakdown

CategoryBeam 1.0 501B A23BClaude Opus 5.5
Task & likeness5.0/108.5/10
Anatomy & construction3.5/107.5/10
Space & placement5.5/107.5/10
Light & reflections4.0/106.0/10
Purposeful detail6.5/108.5/10
Artistry & character3.5/107.0/10
Materials & effects5.0/107.0/10
Visual integrity6.5/108.0/10

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.

Claude Opus 5.5

The recognizable pelican, orderly bicycle wheels and harmonious sunset create an appealing illustration. Both legs connect to the body and reach pedals; no clear detached or inverted parts appear. Steering contact and seating support are less convincing, while the drivetrain remains schematic. Crisp outlines give a clean finish, but limited shading and flat surfaces leave the scene with modest depth.

Score breakdown

CategoryBeam 1.0 501B A23BClaude Opus 5.5
Task & likeness5.5/108.5/10
Anatomy & construction4.5/108.0/10
Space & placement5.0/107.0/10
Light & reflections4.0/106.0/10
Purposeful detail4.0/108.0/10
Artistry & character4.0/107.5/10
Materials & effects4.0/106.0/10
Visual integrity5.5/108.5/10

Benchmark task

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