STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Beam 1.0 501B A23B vs Gemini 3.8 Flash

Gemini 3.8 Flash leads Beam 1.0 501B A23B by 16.0 points on StealthMark, 47.9 to 31.9. It leads on 8 of 9 benchmarks, including Latch, and Beam 1.0 501B A23B on 1, including Foresight. Gemini 3.8 Flash scores higher on Newton's Mirror, with its largest category advantage in materials and scale.

See the difference ↘
All results ↗
All results ↗

Overall StealthMark

31.9/100Overall rank 42/53
47.9/100Overall rank 20/53

General Intelligence

30.9/100
43.9/100

Visual Intelligence

33.8/100
55.2/100

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 modelApache 2.0

BENCHMARK BY BENCHMARK

Where each model leads

  • Beam 1.0 501B A23B
  • Gemini 3.8 Flash
  • Other models
  • Median

DATASHEET

Specs and pricing

Beam 1.0 501B A23B is 3.8× cheaper per output token and runs 5.7× faster in our speed test. Gemini 3.8 Flash scores higher on StealthMark. Both take about 1M tokens of context.

  • Beam 1.0 501B A23B
  • Gemini 3.8 Flash
  • Other models
  • Median
PricePer 1M output tokens, input below
Beam 1.0 501B A23B: $13.8× cheaper$0.25 inputGemini 3.8 Flash: $3.75$0.75 input
Context windowTokens per request, max output below
Beam 1.0 501B A23B: 1MTied128K max outputGemini 3.8 Flash: 1MTied64K max output
Output speedTokens per second, our measurement
Beam 1.0 501B A23B: 9725.7× fastertokens/sGemini 3.8 Flash: 170tokens/s
SizeTotal and active parameters
Beam 1.0 501B A23B: 501B23.4B activeGemini 3.8 Flash: Not disclosed
Developer
Reflection AIGoogle
Released
16 Oct 20262 Sep 2026
Origin
United StatesBoth
Input → output
Text → textText, image, video, audio, PDF → 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 ↗Gemini 3.8 Flash ↗

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

Gemini 3.8 Flash 45.4/100Rank 20/47

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

Points per level

LevelBeam 1.0 501B A23BGemini 3.8 Flash
Level 1Second Thoughts
18 ptsOut of lives
4 ptsOut of lives
Level 2Pressure Pot
9 ptsOut of lives
10 ptsSurvived
Level 3Hide or Flight
9 ptsSurvived
11 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

Gemini 3.8 Flash 72.9/100Rank 14/48

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

Points per level

LevelBeam 1.0 501B A23BGemini 3.8 Flash
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
18.8 ptsCleared
Level 4Passing bay
3.6 ptsFinished early
17.8 ptsClearedFinished early · 1 beacon 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.

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.

Score breakdown

CategoryBeam 1.0 501B A23BGemini 3.8 Flash
State at 600 ms20.5/2522.5/25
Camera and placement11.5/1511.0/15
Reflections2.0/1204.5/120
Materials and scale3.0/107.0/10
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.

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.

Score breakdown

CategoryBeam 1.0 501B A23BGemini 3.8 Flash
Task & likeness4.0/108.0/10
Anatomy & construction3.5/106.0/10
Space & placement5.5/106.5/10
Light & reflections5.5/107.0/10
Purposeful detail4.5/105.0/10
Artistry & character4.0/103.5/10
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.

Gemini 3.8 Flash

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

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.

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.

Score breakdown

CategoryBeam 1.0 501B A23BGemini 3.8 Flash
Task & likeness0.0/103.0/10
Anatomy & construction0.0/102.0/10
Space & placement0.0/103.5/10
Light & reflections0.5/103.0/10
Purposeful detail0.0/105.0/10
Artistry & character0.0/103.0/10
Materials & effects0.0/105.0/10
Visual integrity0.0/101.0/10

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.

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.

Score breakdown

CategoryBeam 1.0 501B A23BGemini 3.8 Flash
Task & likeness7.0/109.0/10
Anatomy & construction5.0/107.0/10
Space & placement6.0/107.0/10
Light & reflections5.0/108.0/10
Purposeful detail5.5/107.0/10
Artistry & character4.0/107.0/10
Materials & effects5.0/107.0/10
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.

Gemini 3.8 Flash

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.

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.

Score breakdown

CategoryBeam 1.0 501B A23BGemini 3.8 Flash
Task & likeness5.0/107.0/10
Anatomy & construction3.5/106.0/10
Space & placement5.5/107.0/10
Light & reflections4.0/106.5/10
Purposeful detail6.5/107.5/10
Artistry & character3.5/107.5/10
Materials & effects5.0/107.5/10
Visual integrity6.5/107.5/10

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

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.

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.

Score breakdown

CategoryBeam 1.0 501B A23BGemini 3.8 Flash
Task & likeness5.5/109.0/10
Anatomy & construction4.5/107.5/10
Space & placement5.0/107.5/10
Light & reflections4.0/107.0/10
Purposeful detail4.0/108.5/10
Artistry & character4.0/108.0/10
Materials & effects4.0/107.0/10
Visual integrity5.5/108.0/10

Benchmark task

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