STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Kimi K3.1 Pro vs Nemotron 3 Ultra

Kimi K3.1 Pro leads Nemotron 3 Ultra by 40.0 points on StealthMark, 56.7 to 16.7. It leads on all 9 benchmarks. Kimi K3.1 Pro 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

56.7/100Overall rank 11/53
16.7/100Overall rank 49/53

General Intelligence

53.9/100
12.2/100

Visual Intelligence

62.0/100
26.5/100

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

BENCHMARK BY BENCHMARK

Where each model leads

  • Kimi K3.1 Pro
  • Nemotron 3 Ultra
  • Other models
  • Median

DATASHEET

Specs and pricing

Kimi K3.1 Pro scores higher on StealthMark. Nemotron 3 Ultra is 4.2× cheaper per output token and runs 19% faster in our speed test. Both take about 1M tokens of context.

  • Kimi K3.1 Pro
  • Nemotron 3 Ultra
  • Other models
  • Median
PricePer 1M output tokens, input below
Kimi K3.1 Pro: $10$2 inputNemotron 3 Ultra: $2.404.2× cheaper$0.60 input
Context windowTokens per request, max output below
Kimi K3.1 Pro: 1MTied1M max outputNemotron 3 Ultra: 1MTied
Output speedTokens per second, our measurement
Kimi K3.1 Pro: 117tokens/sNemotron 3 Ultra: 13919% fastertokens/s
SizeTotal and active parameters
Kimi K3.1 Pro: 2.8T104B activeEstimatedNemotron 3 Ultra: 550B55B active
Developer
Moonshot AINVIDIA
Released
23 Oct 20264 Jun 2026
Origin
ChinaUnited States
Input → output
Text, image, video → textText → text
Architecture
Post-trained version of Kimi K3, a Mixture-of-Experts modelLatentMoE: Mamba-2 + MoE + Attention hybrid with Multi-Token Prediction

Full datasheets, every price and sourceKimi K3.1 Pro ↗Nemotron 3 Ultra ↗

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.

Kimi K3.1 Pro 61.1/100Rank 10/47

Survived 1 of 3
Foresight: complete playing field
Level 315 ptsTurn 20 / 20

Nemotron 3 Ultra 16.9/100Rank 41/47

Survived 0 of 3
Foresight: complete playing field
Level 38 ptsTurn 17 / 20

Points per level

LevelKimi K3.1 ProNemotron 3 Ultra
Level 1Second Thoughts
15 ptsOut of lives
4 ptsOut of lives
Level 2Pressure Pot
12 ptsOut of lives
4 ptsOut of lives
Level 3Hide or Flight
15 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.

Kimi K3.1 Pro 81.8/100Rank 8/48

Cleared 5 of 5
Latch: complete playing field
Level 519.8 ptsTurn 31 / 40

Nemotron 3 Ultra 5.0/100Rank 42/484 of 5 levels

4 of 5 played
Latch: complete playing field
Level 413.8 ptsTurn 21 / 40

Points per level

LevelKimi K3.1 ProNemotron 3 Ultra
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
9.8 ptsCleared
3.2 ptsFinished early
Level 3Relay vault
19.2 ptsCleared
7.4 ptsFinished early
Level 4Passing bay
18.2 ptsClearedFinished early · 3 beacons left
13.8 ptsFinished early
Level 5Second thoughts
19.8 ptsCleared
Not played

Newton's Mirror

Same task instructions

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

The judgment

Kimi K3.1 Pro

The settled sphere, separate airborne black paint and crimson-before-cyan interaction are supported, with a modest crimson travel overshoot. A shared downward framing displacement remains after accounting for the square canvas. The principal limitation is the reflection system: sparse sphere copies and generic curved bands omit most of the ordered mirror-room structure. Materials receive a small upward revision because bounded bright images and dark bands visibly establish some polish, while soft shading and bulky paint remain separate weaknesses.

Nemotron 3 Ultra

The candidate establishes a separate airborne black blob and partial crimson overlap, but leaves the paint interaction history and settled support unresolved. Its main silhouette, black placement and lamp projection depart substantially from the required camera geometry. A few faint reflection hints provide little support for the extensive mirror system, while the compact paint volumes are visibly disproportionate.

Score breakdown

CategoryKimi K3.1 ProNemotron 3 Ultra
State at 600 ms23.5/252.0/25
Camera and placement10.5/153.5/15
Reflections26.0/1204.5/120
Materials and scale7.0/103.0/10
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

Kimi K3.1 Pro

The transformed reflection, attentive pose and constellation anatomy clearly communicate introspection. Purposeful fine details enrich a coherent composition. Tubular limbs, crowded lower-body overlaps, shallow depth and limited cast lighting keep the overall execution within the competent range.

Nemotron 3 Ultra

An endearing mechanical creature is clearly framed, with expressive amber eyes and readable segmented arms. The shell resembles layered green plates more than a deep coiled spiral. Detached-looking construction, absent working contacts and patchy rendering leave the central assembly action substantially unresolved.

Score breakdown

CategoryKimi K3.1 ProNemotron 3 Ultra
Task & likeness8.0/104.0/10
Anatomy & construction5.5/104.0/10
Space & placement6.5/105.5/10
Light & reflections6.5/105.0/10
Purposeful detail7.5/104.0/10
Artistry & character7.0/103.0/10
Materials & effects7.0/104.0/10
Visual integrity7.0/104.5/10

Benchmark task

Kimi K3.1 Pro

An imagined creature encounters its reflection. The scene tests original character design, visual self-interpretation and the relationship between a subject and its reflected image.

Nemotron 3 Ultra

A hovering mechanical nautilus tests spiral construction, connected mechanical forms and contrasting metal and illuminated surfaces.

Mona Lisa

Different task instructions

Precise visual recall and portrait reconstruction.

The judgment

Kimi K3.1 Pro

A coherent, recognizable interpretation with controlled color and readable landscape layers. Replication is limited by the frontal seated construction, elongated facial proportions and oversized, weakly articulated hands. Smooth shading supplies some volume but little of the reference's subtle expression, fabric structure or atmospheric transitions.

Nemotron 3 Ultra

The centered silhouette provides basic organization, but multicolored mottling and geometric overlays leave the portrait unresolved. No readable face, crossed hands, clothing or landscape establishes Mona Lisa replication. Texture and transparency offer limited visual effects without coherent anatomy, lighting or material distinctions.

Score breakdown

CategoryKimi K3.1 ProNemotron 3 Ultra
Task & likeness5.0/100.5/10
Anatomy & construction5.0/100.0/10
Space & placement5.5/101.0/10
Light & reflections6.0/100.5/10
Purposeful detail5.5/100.5/10
Artistry & character6.0/101.5/10
Materials & effects5.0/100.0/10
Visual integrity6.5/100.5/10

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

Kimi K3.1 Pro

A coherent, playful beach illustration with readable animals, an organized composition and an aligned sunset reflection. Connected silhouettes, sand texture and atmospheric effects demonstrate controlled execution. Simplified joints, flattened foreground viewpoints and inconsistent shadows limit anatomical and spatial credibility.

Nemotron 3 Ultra

A recognizable beach illustration with appealing warm-cool contrast, readable layers and mostly clean shapes. Unresolved seat construction, schematic animals and broad geometric foliage give it an elementary finish. Weakly coordinated reflections and limited material differentiation further constrain depth and atmosphere.

Score breakdown

CategoryKimi K3.1 ProNemotron 3 Ultra
Task & likeness8.5/106.5/10
Anatomy & construction5.5/103.0/10
Space & placement5.5/105.0/10
Light & reflections6.5/101.5/10
Purposeful detail6.5/104.5/10
Artistry & character5.5/103.0/10
Materials & effects6.5/102.5/10
Visual integrity7.5/106.5/10

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

Kimi K3.1 Pro

This benchmark has not been assessed yet.

Nemotron 3 Ultra

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

Kimi K3.1 Pro

The additional comparisons support retaining the assessment. Readable steering, shaped animal contours and purposeful details coexist with simplified joints, a frontal passenger whose seated weight is weakly conveyed, and limited physical lighting. The angled craft establishes more depth than the riding pose resolves.

Nemotron 3 Ultra

The masked raccoon, dog and orange craft make the scene recognizable, with an appealing sunset palette. Overlapping bodies obscure the riding relationship, and the dog's connection to the controls remains unresolved. Weak water displacement, inconsistent shading and visible shape artifacts limit the finish. Ambiguous attachments do not establish detached limbs or inverted anatomy.

Score breakdown

CategoryKimi K3.1 ProNemotron 3 Ultra
Task & likeness7.0/103.5/10
Anatomy & construction5.5/101.5/10
Space & placement6.0/104.5/10
Light & reflections5.5/102.0/10
Purposeful detail7.0/103.5/10
Artistry & character6.0/101.5/10
Materials & effects6.0/103.0/10
Visual integrity7.0/102.0/10

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

Kimi K3.1 Pro

A characterful coastal illustration with controlled contours and varied feather, accessory and bicycle detail. Layered scenery and subtle shading enrich the presentation. Soft leg articulation, unresolved riding contacts, shallow depth and generalized lighting limit physical precision.

Nemotron 3 Ultra

A recognizable, playful pelican dominates a readable bicycle scene. Its bill and silhouette succeed, but feet below the pedals and confused drivetrain connections weaken the riding action. Local material modeling adds interest; overlapping contours, repetitive detail and inconsistent shadows leave the illustration basic and uneven.

Score breakdown

CategoryKimi K3.1 ProNemotron 3 Ultra
Task & likeness8.5/104.0/10
Anatomy & construction7.5/103.5/10
Space & placement6.5/103.5/10
Light & reflections6.5/104.0/10
Purposeful detail7.5/105.5/10
Artistry & character7.5/104.0/10
Materials & effects6.5/106.0/10
Visual integrity7.5/103.0/10

Benchmark task

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