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Grok-4 Heavy vs Solar Pro 4

Grok-4 Heavy leads the LLM Stats Score 40.7 to 35.2.

xAI · Upstage · Updated for 2026

Which is better?

Grok-4 Heavy leads the overall LLM Stats Score 40.7 to 35.2, ranking #54 overall.

In the 2 individual benchmarks reported for both models, Solar Pro 4 wins 2; this is a narrower head-to-head signal than the composite indexes.

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

Choose Grok-4 Heavy

  • overall performance matters — it scores 40.7 and ranks #54 on LLM Stats

Choose Solar Pro 4

  • you value its reported benchmark strengths — it wins 2 of 2 exact shared results

At a glance

The differences that matter most.

Core performance indexes
40.7
#54
35.2
#87
39.0
#58
34.8
#83
17.7
#115
21.1
#90
Cost, coverage & limits
Benchmark wins
0 of 2
2 of 2
Input price
— / M
$0.30 / M
Output price
— / M
$1.20 / M
Context window
524,288

Capability indexes

Additional strengths measured across groups of related public benchmarks

1 shared
Index
Grok-4 Heavy
Solar Pro 4
41.5#6
32.3#60
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

6 reported for Grok-4 Heavy · 9 for Solar Pro 4

2 shared

Grok-4 Heavy outperforms in 0 benchmarks, while Solar Pro 4 is better at 2 benchmarks (GPQA, LiveCodeBench).

Solar Pro 4 significantly outperforms across most benchmarks.

Mon Sep 21 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only Solar Pro 4 specifies input context (524,288 tokens). Only Solar Pro 4 specifies output context (131,072 tokens).

xAI
Grok-4 Heavy
Input- tokens
Output- tokens
Upstage
Solar Pro 4
Input524,288 tokens
Output131,072 tokens
Mon Sep 21 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Grok-4 Heavy supports multimodal inputs, whereas Solar Pro 4 does not.

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

Grok-4 Heavy

Text
Images
Audio
Video

Solar Pro 4

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Grok-4 Heavy

Proprietary

Closed source

Solar Pro 4

Proprietary

Closed source

Release Timeline

When each model was launched

Solar Pro 4 was released on 2026-08-06, while Grok-4 Heavy's release date is not specified.

We can confirm Solar Pro 4's release timeline, but cannot make a direct age comparison without Grok-4 Heavy's release date.

Grok-4 Heavy

Solar Pro 4

Aug 6, 2026

1 months ago

Knowledge Cutoff

When training data ends

Grok-4 Heavy has a documented knowledge cutoff of 2024-12-31, while Solar Pro 4's cutoff date is not specified.

We can confirm Grok-4 Heavy's training data extends to 2024-12-31, but cannot make a direct comparison without Solar Pro 4's cutoff date.

Grok-4 Heavy

Dec 2024

Solar Pro 4

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion

Judge for yourself.

Run your own prompts against Grok-4 Heavy and Solar Pro 4 side-by-side, then vote on the output you prefer.

Grok-4 Heavy
✓ Preferred
Solar Pro 4
Open in Playground

FAQ

Common questions about Grok-4 Heavy vs Solar Pro 4.

Which is better, Grok-4 Heavy or Solar Pro 4?

Grok-4 Heavy leads the LLM Stats Score 40.7 to 35.2. Grok-4 Heavy is made by xAI and Solar Pro 4 is made by Upstage. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Grok-4 Heavy compare to Solar Pro 4 in benchmarks?

Grok-4 Heavy scores AIME 2025: 100.0%, HMMT25: 96.7%, GPQA: 88.4%, LiveCodeBench: 79.4%, USAMO25: 61.9%. Solar Pro 4 scores AIME 2026: 95.3%, GPQA: 89.0%, LiveCodeBench: 87.8%, MMLU-Pro: 86.3%, AA-LCR: 71.0%.

What are the context window sizes for Grok-4 Heavy and Solar Pro 4?

Grok-4 Heavy supports an unknown number of tokens and Solar Pro 4 supports 524K 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 Heavy and Solar Pro 4?

Key differences include LLM Stats Score (40.7 vs 35.2), multimodal support (yes vs no). See the full comparison above for benchmark-by-benchmark results.

Who makes Grok-4 Heavy and Solar Pro 4?

Grok-4 Heavy is developed by xAI and Solar Pro 4 is developed by Upstage.