STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Hy4 preview vs Step 5 Preview

Hy4 preview leads Step 5 Preview by 4.9 points on StealthMark, 43.9 to 39.0. It leads on 7 of 9 benchmarks, including Foresight, and Step 5 Preview on 2, including Latch. Hy4 preview scores higher on Beach, with its largest category advantage in prompt & likeness.

See the difference ↘
All results ↗
All results ↗

Overall StealthMark

43.9/100Overall rank 30/53
39.0/100Overall rank 36/53

General Intelligence

41.3/100
37.1/100

Visual Intelligence

48.6/100
41.9/100

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

  • Hy4 preview

Open or local

Open modelApache-2.0

BENCHMARK BY BENCHMARK

Where each model leads

  • Hy4 preview
  • Step 5 Preview
  • Other models
  • Median

DATASHEET

Specs and pricing

Both take about 1M tokens of context.

  • Hy4 preview
  • Step 5 Preview
  • Other models
  • Median
PricePer 1M output tokens, input below
Hy4 preview: $2.50$0.83 inputStep 5 Preview: No list price
Context windowTokens per request, max output below
Hy4 preview: 1MTied64K max outputStep 5 Preview: 1MTied
Output speedTokens per second, our measurement
Hy4 preview: 64tokens/sStep 5 Preview: Not measured
SizeTotal and active parameters
Hy4 preview: 770B49B activeStep 5 Preview: 600B27B active
Developer
Tencent Hy TeamStepFun
Released
28 Aug 2026Not published
Origin
ChinaNot published
Input → output
Text → textText, image, video → text
Architecture
MoE; 78-layer backbone with Gated DSA, 256 routed experts + 1 shared expert, top-8 routed experts active, plus native MTP layerSparse mixture-of-experts; 92 layers (88 MoE), 352 routed experts with 8 selected per token plus a shared expert; grouped-query attention with 512-token sliding windows and full attention every fourth layer; 3 multi-token-prediction layers; vision tower for image and video input

Full datasheets, every price and sourceHy4 preview ↗Step 5 Preview ↗

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.

Hy4 preview 53.1/100Rank 14/49

Survived 1 of 3
Foresight: complete playing field
Level 311 ptsTurn 16 / 20

Step 5 Preview 59.9/100Rank 42/491 of 3 levels

1 of 3 played
Foresight: complete playing field
Level 122 ptsTurn 28 / 28

Points per level

LevelHy4 previewStep 5 Preview
Level 1Second Thoughts
26 ptsSurvived
22 ptsSurvived
Level 2Pressure Pot
6 ptsOut of lives
Pending
Level 3Hide or Flight
11 ptsOut of lives
Pending

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.

Hy4 preview 35.6/100Rank 33/50

Cleared 3 of 5
Latch: complete playing field
Level 518.2 ptsTurn 19 / 40

Step 5 Preview 40.7/100Rank 28/50

Cleared 4 of 5
Latch: complete playing field
Level 515 ptsTurn 35 / 40

Points per level

LevelHy4 previewStep 5 Preview
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
6 ptsFinished early
9 ptsCleared
Level 3Relay vault
18 ptsCleared
18.6 ptsCleared
Level 4Passing bay
15.8 ptsClearedFinished early · 3 beacons left
15.6 ptsClearedFinished early · 3 beacons left
Level 5Second thoughts
18.2 ptsFinished early
15 ptsFinished early

Newton's Mirror

Same task instructions

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

The judgment

Hy4 preview

The central sphere, compact airborne black bead and broad paint ordering are supported. Contact and transport history remain partly unresolved. The optical system provides only isolated first images and light patches, with little evidence of the extensive ordered reflection structure. Rounded metal and paint gloss are more successful than the reflected contents.

Step 5 Preview

The main sphere, airborne black and small colored features occupy broadly appropriate positions. Most of the defining mirror system is absent, and paint interaction remains only partially supported. The small paint features do not visibly establish a separate volume-scale violation.

Score breakdown

CategoryHy4 previewStep 5 Preview
State at 600 ms18.0/2520.0/25
Camera and placement11.5/1513.5/15
Reflections29.5/12020.0/120
Materials and scale7.5/107.0/10
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

Hy4 preview

A cohesive, appealing illustration with a serene face, luminous palette and complete framing. The separated head and torso weaken anatomical coherence, while crowded wing attachments and angular sash folds limit the requested suppleness. Clean execution and decorative detail exceed the clarity of the underlying construction.

Step 5 Preview

A charming diagonal climber and warm palette communicate the central idea. Simple rounded construction, crowded limb counting, uncertain footholds and an unattached upper shelf limit its physical coherence. Growth bands and the yarn trail add specificity, but the requested material distinctions and unravelled bootie remain underdeveloped.

Score breakdown

CategoryHy4 previewStep 5 Preview
Task & likeness6.0/106.0/10
Anatomy & construction5.5/104.5/10
Space & placement7.5/105.0/10
Light & reflections7.0/105.5/10
Purposeful detail6.5/105.5/10
Artistry & character5.0/105.0/10
Materials & effects7.0/106.0/10
Visual integrity5.5/105.0/10

Benchmark task

Hy4 preview

A young blue dragon floating among clouds tests curved anatomy, expressive features and the contrast between soft clouds and glossy surfaces.

Step 5 Preview

Character scenes test expression, anatomy, materials and coherent visual construction.

Mona Lisa

Different task instructions

Precise visual recall and portrait reconstruction.

The judgment

Hy4 preview

A recognizable but basic Mona Lisa interpretation with a cohesive earthy palette and atmospheric hills. The rigid neck, generic face and unresolved folded-hand pose limit replication and anatomy. Large silhouettes and layer boundaries are comparatively clear, warranting stronger integrity credit than the sparse detail and simplified construction.

Step 5 Preview

A recognizable, coherent simplification with purposeful facial contours and differentiated fingers. These provide more construction and detail than the broad silhouette alone suggests. The oversized face, frontal seated pose, unresolved wrists and sparse landscape still substantially limit likeness, depth and finish.

Score breakdown

CategoryHy4 previewStep 5 Preview
Task & likeness2.5/104.0/10
Anatomy & construction2.5/104.0/10
Space & placement2.5/104.0/10
Light & reflections1.5/103.5/10
Purposeful detail2.5/104.0/10
Artistry & character1.5/104.0/10
Materials & effects2.5/103.0/10
Visual integrity4.0/103.5/10

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

Hy4 preview

A cheerful beach illustration fulfills the visible subject requirements with coherent foreground construction and a harmonious sunset palette. Shallow depth, schematic reflections, ambiguous blue airborne forms and exposed geometry beneath the sunset limit its finish. Small accessories are readable, but materials and surface detail remain simplified.

Step 5 Preview

A recognizable sunset beach with clear warm-cool contrast and playful accessories. Basic animal construction, shallow foreground placement and schematic reflections limit spatial and physical credibility. Sparse descriptive detail and abruptly ended sky bands constrain the finish.

Score breakdown

CategoryHy4 previewStep 5 Preview
Task & likeness8.5/104.0/10
Anatomy & construction5.5/103.0/10
Space & placement6.5/103.5/10
Light & reflections5.0/103.5/10
Purposeful detail6.0/103.0/10
Artistry & character5.5/103.0/10
Materials & effects5.0/103.5/10
Visual integrity6.0/104.0/10

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

Hy4 preview

This benchmark has not been assessed yet.

Step 5 Preview

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

Hy4 preview

A lively cartoon communicates the animal pair traveling across water. Curving waves, rising spray and locally modeled gray forms strengthen motion and volume. Ambiguous seating, simplified joints and unclear control routing limit construction. Competing focal elements, decorative foam and inconsistent illumination leave the finish uneven.

Step 5 Preview

Recognizable animals, a bright palette and identifying accessories support a basic cartoon. Primitive anatomy, partial seated support, unresolved steering and weak hull-water contact limit the central action. Lighting and spray provide atmosphere without establishing convincing physical depth.

Score breakdown

CategoryHy4 previewStep 5 Preview
Task & likeness7.0/104.0/10
Anatomy & construction4.0/104.5/10
Space & placement6.0/103.0/10
Light & reflections6.5/103.5/10
Purposeful detail5.5/104.0/10
Artistry & character4.5/103.5/10
Materials & effects5.5/103.0/10
Visual integrity5.0/103.0/10

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

Same task instructions

Subject construction and spatial relationships.

The judgment

Hy4 preview

A recognizable, playful pelican cyclist with readable wheels, accessories and landscape layers. Form shading and ground shadows provide competent depth. Angular legs, uncertain pedal engagement and absent steering contact limit the riding construction; crowded overlaps and simple surfaces constrain refinement.

Step 5 Preview

The pelican and bicycle are recognizable, with a pleasant palette and basic diffuse shading. The riding relationship fails physically: the bird is unsupported, the front wheel is unmounted, and pedalling is unresolved. Simple geometric construction and sparse material treatment further limit the drawing.

Score breakdown

CategoryHy4 previewStep 5 Preview
Task & likeness7.5/103.0/10
Anatomy & construction4.5/103.0/10
Space & placement6.5/103.0/10
Light & reflections7.0/103.0/10
Purposeful detail6.0/104.0/10
Artistry & character5.0/103.0/10
Materials & effects5.0/103.0/10
Visual integrity7.0/102.0/10

Benchmark task

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