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Model comparison

Grok 4.6 vs Step 5 Preview

SpaceXAI against StepFun, compared on context, price, and verified benchmark results.

Catalog record checked September 26, 2026Individual provider fields may changeEvidence confidence: Medium — see receipts below

SpaceXAI

Grok 4.6

Frontier

vs

StepFun

Step 5 Preview

Frontier

AI model capability comparison
SpecificationGrok 4.6Step 5 Preview
ProviderSpaceXAIStepFun
TierFrontierFrontier
Context window500KWinner: 1M
Max outputNot verifiedUnverifiedNot verifiedUnverified
Input / 1M tokens$2Winner: $1
Output / 1M tokens$6Winner: $2.70
WeightsClosedClosed
ParametersNot disclosedUnverified600B total / 27B active MoE (StepFun)
Reasoning levelslow, medium, high, xhighNot verifiedUnverified
Modalitiestext, imagetext, image
API model idgrok-4.6step-5-preview
ReleasedAugust 12, 2026September 18, 2026
Artificial Analysis Intelligence Index [high] (2026-09-26)44.3Not verifiedUnverified
Artificial Analysis Intelligence Index (2026-09-26)Not verifiedUnverified43.7
Terminal-Bench 2.1 (2026-08-18)88Not verifiedUnverified
GPQA Diamond (2026-08-18)94.9Not verifiedUnverified

Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Bold indicates the better figure where one is objectively better. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.

Benchmark receipts

Where each score comes from, and how far it can be compared across models.

  • 2026-09-26
    Artificial Analysis

    Composite index blending reasoning, knowledge, and coding evals into one 0–100 score.

    Comparable with caveatOnly same-version scores are comparable. v4.3.2 was rebaselined (the top score fell from 66 on v4.1.1 to ~58), so v4.1.1 figures must not be compared with v4.3.2 figures — check measuredAt.

  • 2026-08-18
    Artificial Analysis measurement (independent, high effort)

    Agentic terminal work: multi-step tasks executed in a sandboxed shell environment.

    Comparable with caveatNot comparable with Terminal-Bench 3.0 or 4.0 (different task sets) or v1; harness configuration (container, time limits) also shifts results.

Pricing tiers

Grok 4.6: $2/$6 per MTok (<200K prompt); $4/$12 (≥200K). Cached input $0.50/MTok ($1.00 at ≥200K). xAI's release notes list no separate text-output cap (bounded by the 500K context).

Step 5 Preview: $1.00/$2.70 per MTok on the StepFun platform (cache-hit input $0.05); StepFun lists it under Multimodal Reasoning Models and says output tokens include reasoning. No max-output figure is published. StepFun says open weights follow on 2026-10-15. Release date per Artificial Analysis's listing (StepFun's launch page is undated).

FrontierRecord checked September 26, 2026

Grok 4.6

Grok 4.6 was xAI's August 2026 coding flagship, superseded by Grok 4.7 (2026-09-21) at the same $2/$6 price.

Best for

  • Coding agents
  • Chat and knowledge
  • Cost-sensitive frontier work

Watch out

Superseded — xAI's docs now say to use Grok 4.7 at the same price. Token rates double above a 200K-token prompt.

FrontierRecord checked September 26, 2026

Step 5 Preview

Step 5 Preview is StepFun's new frontier reasoning model — a 1M-context, vision-input API preview that lands near Kimi K3 and GLM 5.3 on the Artificial Analysis index at a lower price.

Best for

  • Long-context work on a budget
  • Chinese + English
  • Early testing before the open-weight drop

Watch out

Preview: weights are promised for 2026-10-15 but not yet released, and its max output is unpublished and the launch benchmarks are vendor-run.

When the cheaper one wins

Step 5 Preview is cheaper on output at $2.70 per million tokens against $6 for Grok 4.6 — about 2.2×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. These are standard-tier API rates, excluding batch and cache discounts.

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Evidence confidence: Medium

How strong and complete the evidence behind this comparison is — not a prediction of which model is better.

  • Pricing verified on both sides — Input and output rates are verified for both models.
  • 2/5 core specs verified on both sides — Not published for at least one side: max output, parameter count, reasoning levels.
  • 1 shared named benchmark (scores match) — Measured on: Artificial Analysis Intelligence Index — scores are equivalent, so the benchmark does not separate the pair.
  • Verified within the last 90 days — Newest catalog check was 2 days ago.
  • Both models carry source citations — Each side has at least two catalog sources on record.

Source receipts

Each catalog figure was checked against the provider or an independent second source on the date shown.

Related comparisons

Diving deeper on one model? Grok 4.6 · Step 5 Preview

Common questions

Grok 4.6 vs Step 5 Preview

Answered from the verified figures on this page rather than general guidance.

Is Grok 4.6 or Step 5 Preview cheaper for input?
Step 5 Preview is cheaper at $1 per million input tokens, against $2 for Grok 4.6 — roughly 2.0× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; Grok 4.6 has tiered pricing: $2/$6 per MTok (<200K prompt); $4/$12 (≥200K). Cached input $0.50/MTok ($1.00 at ≥200K). xAI's release notes list no separate text-output cap (bounded by the 500K context). Step 5 Preview has tiered pricing: $1.00/$2.70 per MTok on the StepFun platform (cache-hit input $0.05); StepFun lists it under Multimodal Reasoning Models and says output tokens include reasoning. No max-output figure is published. StepFun says open weights follow on 2026-10-15. Release date per Artificial Analysis's listing (StepFun's launch page is undated).
Is Grok 4.6 or Step 5 Preview cheaper for output?
Step 5 Preview is cheaper at $2.70 per million output tokens, against $6 for Grok 4.6 — roughly 2.2× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; Grok 4.6 has tiered pricing: $2/$6 per MTok (<200K prompt); $4/$12 (≥200K). Cached input $0.50/MTok ($1.00 at ≥200K). xAI's release notes list no separate text-output cap (bounded by the 500K context). Step 5 Preview has tiered pricing: $1.00/$2.70 per MTok on the StepFun platform (cache-hit input $0.05); StepFun lists it under Multimodal Reasoning Models and says output tokens include reasoning. No max-output figure is published. StepFun says open weights follow on 2026-10-15. Release date per Artificial Analysis's listing (StepFun's launch page is undated).
Which has the larger context window, Grok 4.6 or Step 5 Preview?
Step 5 Preview accepts 1M tokens against 500K for Grok 4.6. This only matters if you routinely send very long documents or large codebases.
Should I use Grok 4.6 or Step 5 Preview?
Both sit in the frontier tier, so the choice usually comes down to price and context rather than capability. Grok 4.6 suits coding agents; Step 5 Preview suits long-context work on a budget.

Next step

Choosing between them

The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.

  • Input price: Step 5 Preview costs $1 per 1M tokens versus $2 for Grok 4.6 — a 2x difference at the headline tier.
  • Context: Step 5 Preview takes 1M against 500K for Grok 4.6 — only decisive if your prompts approach the smaller window.
  • Measured capability: Grok 4.6 leads Artificial Analysis Intelligence Index 44.3 to 43.7 (measured 2026-09-26).
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