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BenchLM

Grok 4.20 vs Grok Voice Think Fast 1.0

Decision reading

The public evidence has no benchmark result shared by both models, so it does not support a quality verdict. Use the documented cost, context, and runtime rows instead.

0 results are shared. Category rows resting on Estimated evidence or different benchmark sets are marked directional and do not name a winner.

xAI logo
Model A
Grok 4.20

xAI

67.27/100

Supported · Public rank #29

90% interval 58.7–75.8

xAI logo
Model B
Grok Voice Think Fast 1.0

xAI

—

Evidence status unavailable

90% interval unavailable

Updated September 18, 2026. We do not rank this pair: at least one has no public score. Public scores include evidence status and uncertainty.

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Which one for your work

Recommendations appear only when a shared evidence basis or an explicit operating constraint supports the call. Secondary and unsupported use cases stay disclosed below the initial list.

No workload recommendation clears the current evidence threshold.

Use the matched evidence, workload costs, and sourced specifications below instead of treating a point score as a universal answer.

Show secondary and unsupported calls

  • Coding work

    Code generation, repair, and software-engineering tasks

    Not enough matched evidence

    Grok Voice Think Fast 1.0 is not ranked on the public lane for coding, so no winner is named for coding.

    Confidence: limited

  • Agentic work

    Tool use, computer use, and multi-step task completion

    Not enough matched evidence

    Grok Voice Think Fast 1.0 is not ranked on the public lane for agentic, so no winner is named for agentic.

    Confidence: limited

  • Long documents

    Prompts that approach the documented context limit

    Not enough matched evidence

    A complete context comparison is not sourced.

    Confidence: limited

  • Chat turn cost

    1K fresh input + 500 output tokens

    Not enough matched evidence

    A complete comparable API-rate estimate is not available for both models.

    Confidence: listed-rates

  • Cache-heavy agent loop cost

    200K cached + 20K fresh input + 10K output tokens

    Not enough matched evidence

    A complete comparable API-rate estimate is not available for both models.

    Confidence: rate-fallback

  • Repository review cost

    50K fresh input + 3K output tokens

    Not enough matched evidence

    A complete comparable API-rate estimate is not available for both models.

    Confidence: listed-rates

Which one for a specific job

Choose a job from the LLM Selector's task catalog to see the category row it rests on, under the same basis rules as the table below. A directional row stays directional; choosing a job never creates a winner.

The same task catalog as the LLM Selector. Each job names the evidence surface it rests on; nothing here adds a new score.

28.3Grok 4.20—Grok Voice Think Fast 1.0

Not comparable · BenchAlign

The coding row is not comparable on the public lane: at least one model is not measured or not ranked there.

Coding scores combine specific tasks and setups. Match the editor, harness, and effort to your workflow.

Open the coding leaderboardShortlist models for this job

What is actually comparable

Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.

Shared results
0
Grok 4.20 only
23
Grok Voice Think Fast 1.0 only
0
Like-for-like categories
0 / 8

Category results, on a stated basis

Each row shows the public-lane category score for both models: the BenchAlign lane for agentic, coding, and knowledge, and the weighted public rows elsewhere, with the same rank each model page reports. A row is like-for-like only when both scores rest on Supported evidence or the same weighted set. Directional and not-comparable rows remain visible, but they never receive a winner.

Agentic

Not comparable
Grok 4.20
26.5
Supported · #149/154
Grok Voice Think Fast 1.0
Not ranked
Basis
BenchAlign lane · 4 vs 0 public rows
Reading
Not comparable

Coding

Not comparable
Grok 4.20
28.3
Supported · #145/154
Grok Voice Think Fast 1.0
Not ranked
Basis
BenchAlign lane · 6 vs 0 public rows
Reading
Not comparable

Reasoning

Not comparable
Grok 4.20
34.3
Unranked · 2 rankable rows
Grok Voice Think Fast 1.0
Not ranked
Basis
Provisional lane · 2 vs 0 weighted rows
Reading
Not comparable

Knowledge

Not comparable
Grok 4.20
49.2
Supported · #87/184
Grok Voice Think Fast 1.0
Not ranked
Basis
BenchAlign lane · 6 vs 0 public rows
Reading
Not comparable

Math

Not comparable
Grok 4.20
Not ranked
Grok Voice Think Fast 1.0
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Multilingual

Not comparable
Grok 4.20
Not ranked
Grok Voice Think Fast 1.0
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Multimodal

Not comparable
Grok 4.20
34.6
#43/48
Grok Voice Think Fast 1.0
Not ranked
Basis
Provisional lane · 2 vs 0 weighted rows
Reading
Not comparable

Instruction following

Not comparable
Grok 4.20
Not ranked
Grok Voice Think Fast 1.0
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Ranks count the models scored in each category’s lane, so the agentic, coding, and knowledge denominators (BenchAlign) differ from the provisional-lane categories. Unranked scores sit on the lane’s scale but never name a winner. Like-for-like rows within 0.5 points read as a practical tie.

Shape of the matched evidence

Only shared public evidence is shown. Sparse evidence stays a ruled list rather than being closed into a radar shape.

A shared-evidence shape is not available.

BenchLM does not draw a radar or infer missing axes when the matched evidence is too sparse.

What each workload costs

Three fixed token mixes turn per-token rates into comparable decisions. Each scenario states context fit and whether cached input had to fall back to the published list-input rate.

Chat turn

1K fresh input + 500 output tokens

Grok 4.20
$0.005
Fits in one request
Grok Voice Think Fast 1.0
API rate not published
Fit state unavailable

Grok Voice Think Fast 1.0 has no comparable published API token rate.

Repository review

50K fresh input + 3K output tokens

Grok 4.20
$0.118
Fits in one request
Grok Voice Think Fast 1.0
API rate not published
Fit state unavailable

Grok Voice Think Fast 1.0 has no comparable published API token rate.

Cache-heavy agent loop

200K cached + 20K fresh input + 10K output tokens

Grok 4.20
$0.5
Fits in one request
Cached input priced at the published list-input rate
Grok Voice Think Fast 1.0
API rate not published
Fit state unavailable
Cached-input rate unavailable

Grok 4.20 has no published cached-input rate, so cached tokens use its listed input rate. Grok Voice Think Fast 1.0 has no comparable published API token rate.

Specification differences

Sourced differences are shown directly. Missing facts stay explicit instead of being inferred from a model name or family.

Context window

Maximum documented context; output-token limits may be lower.

Grok 4.20

2M

Grok Voice Think Fast 1.0

N/A

Cached-input rate

A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.

Grok 4.20

Not published

Grok Voice Think Fast 1.0

No comparable hosted API rate

xAI model documentation

Documented inputs

Grok 4.20

Not sourced

Grok Voice Think Fast 1.0

Not sourced

Documented outputs

Grok 4.20

Not sourced

Grok Voice Think Fast 1.0

Not sourced

Provider availability

Grok 4.20

Not sourced

Grok Voice Think Fast 1.0

Not sourced

Reasoning profile

Grok 4.20

Reasoning

Grok Voice Think Fast 1.0

Non-Reasoning

Weight access

Grok 4.20

Proprietary

Grok Voice Think Fast 1.0

Proprietary

License

Grok 4.20

Proprietary

Grok Voice Think Fast 1.0

Proprietary

Release date

Grok 4.20

2026-03-10

Grok Voice Think Fast 1.0

Not sourced

If you already use one of these models
Deployment change
Both entries list xAI as the provider. Confirm endpoint, model ID, limits, and feature support before switching.
Quality signal
The public evidence has no benchmark result shared by both models, so it does not support a quality verdict.
Workload cost
A complete comparable API-rate estimate is not available for both models.
Context tradeoff
A complete documented context comparison is not available.

Run the same representative tasks against both endpoints before changing production traffic.

Benchmark evidence

The full public result ledger is available for audit without forcing a wide desktop table onto a phone.

Browse raw public benchmark evidence23 rows

Agentic

  • Terminal-Bench 2.0

    Grok 4.2047.1%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • DeepSearchQA

    Grok 4.2062.8%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • Gert Labs

    Grok 4.2038.36%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • Terminal-Bench 2.1 (Vals)

    Grok 4.2044.2%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

Coding

  • LiveCodeBench Pro

    Grok 4.2074.2%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • SWE-bench Verified

    Grok 4.2076.7%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • SWE-bench Pro

    Grok 4.2051.8%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • Vibe Code Bench

    Grok 4.204.06%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • LiveCodeBench (Vals)

    Grok 4.2084.3%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • SWE-bench (Vals)

    Grok 4.2072.2%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

Reasoning

  • ARC-AGI-2

    Grok 4.2053.3%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • ARC-AGI-3

    Grok 4.200.1%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

Knowledge

  • GPQA-D

    Grok 4.2088.5%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • HLE w/o tools

    Grok 4.2031.6%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • HealthBench Hard

    Grok 4.2020.3%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • MedXpertQA (Text)

    Grok 4.2050.2%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • GPQA Diamond (Vals)

    Grok 4.2088.6%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • MMLU-Pro (Vals)

    Grok 4.2086.3%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

Multimodal

  • MMMU-Pro

    Grok 4.2075.2%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • CharXiv

    Grok 4.2060.9%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • ERQA

    Grok 4.2054.1%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • SimpleVQA

    Grok 4.2057.4%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

  • MedXpertQA (MM)

    Grok 4.2065.8%
    Source
    Grok Voice Think Fast 1.0—

    Not directly comparable

Questions

Which is better, Grok 4.20 or Grok Voice Think Fast 1.0?

The public evidence has no benchmark result shared by both models, so it does not support a quality verdict. The page therefore keeps the decision tied to the specific documented workload.

Which is better for coding, Grok 4.20 or Grok Voice Think Fast 1.0?

Grok Voice Think Fast 1.0 is not ranked on the public lane for coding, so no winner is named for coding.

Which is better for agentic tasks, Grok 4.20 or Grok Voice Think Fast 1.0?

Grok Voice Think Fast 1.0 is not ranked on the public lane for agentic tasks, so no winner is named for agentic tasks.

Which costs less, Grok 4.20 or Grok Voice Think Fast 1.0?

Both models do not have comparable published API token rates, so this page does not name a universal price winner.

Which has the larger context window, Grok 4.20 or Grok Voice Think Fast 1.0?

A complete documented context-window comparison is not available.

Related comparisons

Compare API pricing Read the methodology Open the model selector

Last updated September 18, 2026

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