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Grok 4 Fast vs K2 Horizon 7B

Grok 4 Fast and K2 Horizon 7B are closely matched at 30.9 and 25.7 on the LLM Stats Score.

xAI · Institute of Foundation Models · Updated for 2026

Which is better?

Grok 4 Fast and K2 Horizon 7B are closely matched on the overall LLM Stats Score at 30.9 and 25.7.

The models split the 2 individual benchmarks reported for both models evenly.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Grok 4 Fast

  • your work emphasizes coding — it leads those capability indexes

Choose K2 Horizon 7B

  • you want the most recent training data — it shipped Sep 2026
  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

Grok 4 Fast
xAI
K2 Horizon 7B
Institute of Foundation Models
Core performance indexes
LLM Stats Score
30.9
#140
25.7
#184
Reasoning
30.0
#146
25.6
#181
Coding
18.0
#140
8.4
#209
Agents
2.1
#199
12.0
#133
Cost, coverage & limits
Benchmark wins
1 of 2
1 of 2
Input price
$0.20 / M
— / M
Output price
$0.50 / M
— / M
Context window
2,000,000
—

Capability indexes

Additional strengths measured across groups of related public benchmarks

1 shared
Index
Grok 4 Fast
K2 Horizon 7B
Math
27.1#109
14.4#235
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

7 reported for Grok 4 Fast · 8 for K2 Horizon 7B

2 shared

Grok 4 Fast outperforms in 1 benchmarks (Humanity's Last Exam), while K2 Horizon 7B is better at 1 benchmark (BrowseComp).

Both models are evenly matched across the benchmarks.

Fri Oct 30 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only Grok 4 Fast specifies input context (2,000,000 tokens). Only Grok 4 Fast specifies output context (30,000 tokens).

xAI
Grok 4 Fast
Input2,000,000 tokens
Output30,000 tokens
Institute of Foundation Models
K2 Horizon 7B
Input- tokens
Output- tokens
Fri Oct 30 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Grok 4 Fast supports multimodal inputs, whereas K2 Horizon 7B does not.

Grok 4 Fast can handle both text and other forms of data like images, making it suitable for multimodal applications.

Grok 4 Fast

Text
Images
Audio
Video

K2 Horizon 7B

Text
Images
Audio
Video

License

Usage and distribution terms

Grok 4 Fast is licensed under a proprietary license, while K2 Horizon 7B uses Apache 2.0.

License differences may affect how you can use these models in commercial or open-source projects.

Grok 4 Fast

Proprietary

Closed source

K2 Horizon 7B

Apache 2.0

Open weights

Release Timeline

When each model was launched

Grok 4 Fast was released on 2025-08-28, while K2 Horizon 7B was released on 2026-09-03.

K2 Horizon 7B is 12 months newer than Grok 4 Fast.

Grok 4 Fast

Aug 28, 2025

1.2 years ago

K2 Horizon 7B

Sep 3, 2026

1 months ago

1.0yr newer

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against Grok 4 Fast and K2 Horizon 7B side-by-side, then vote on the output you prefer.

Grok 4 Fast
✓ Preferred
K2 Horizon 7B
Open in Playground

FAQ

Common questions about Grok 4 Fast vs K2 Horizon 7B.

Which is better, Grok 4 Fast or K2 Horizon 7B?

Grok 4 Fast and K2 Horizon 7B are closely matched on the LLM Stats Score at 30.9 and 25.7. Grok 4 Fast is made by xAI and K2 Horizon 7B is made by Institute of Foundation Models. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Grok 4 Fast compare to K2 Horizon 7B in benchmarks?

Grok 4 Fast scores SimpleQA: 95.0%, HMMT 2025: 93.3%, AIME 2025: 92.0%, GPQA: 85.7%, LiveCodeBench: 80.0%. K2 Horizon 7B scores HMMT Feb 26: 73.3%, SWE-Bench Verified: 70.6%, AA-LCR: 68.0%, BrowseComp: 59.0%, Terminal-Bench 2.1: 39.1%.

What are the context window sizes for Grok 4 Fast and K2 Horizon 7B?

Grok 4 Fast supports 2.0M tokens and K2 Horizon 7B supports an unknown number of tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Grok 4 Fast and K2 Horizon 7B?

Key differences include LLM Stats Score (30.9 vs 25.7), multimodal support (yes vs no), licensing (Proprietary vs Apache 2.0). See the full comparison above for benchmark-by-benchmark results.

Who makes Grok 4 Fast and K2 Horizon 7B?

Grok 4 Fast is developed by xAI and K2 Horizon 7B is developed by Institute of Foundation Models.

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