| Signal | Grok 4 Fast | Delta | Sonar Reasoning Pro |
|---|---|---|---|
Capabilities | 100 | +33 | |
Benchmarks | 70 | +70 | |
Pricing | 1 | -7 | |
Context window size | 100 | +19 | |
Recency | 99 | +36 | |
Output Capacity | 75 | +55 | |
| Overall Result | 5 wins | of 6 | 1 wins |
30
days ranked higher
0
days
0
days ranked higher
xAI
Perplexity
Grok 4 Fast saves you $555.00/month
That's $6660.00/year compared to Sonar Reasoning Pro at your current usage level of 100K calls/month.
| Metric | Grok 4 Fast | Sonar Reasoning Pro | Winner |
|---|---|---|---|
| Overall Score | 83 | 62 | Grok 4 Fast |
| Rank | #52 | #215 | Grok 4 Fast |
| Quality Rank | #52 | #215 | Grok 4 Fast |
| Adoption Rank | #52 | #215 | Grok 4 Fast |
| Parameters | -- | -- | -- |
| Context Window | 2000K | 128K | Grok 4 Fast |
| Pricing | $0.20/$0.50/M | $2.00/$8.00/M | -- |
| Signal Scores | |||
| Capabilities | 100 | 67 | Grok 4 Fast |
| Benchmarks | 70 | -- | Grok 4 Fast |
| Pricing | 1 | 8 | Sonar Reasoning Pro |
| Context window size | 100 | 81 | Grok 4 Fast |
| Recency | 99 | 64 | Grok 4 Fast |
| Output Capacity | 75 | 20 | Grok 4 Fast |
Our composite score (0–100) combines six weighted signals: benchmark performance (25%), pricing efficiency (25%), context window size (15%), model recency (15%), output capacity (10%), and capability versatility (10%). Here's what the scores mean for these two models:
Scores 83/100 (rank #52), placing it in the top 82% of all 290 models tracked.
Scores 62/100 (rank #215), placing it in the top 26% of all 290 models tracked.
Grok 4 Fast has a 22-point advantage, which typically translates to noticeably stronger performance on complex reasoning, code generation, and multi-step tasks.
Grok 4 Fast offers 93% better value per quality point. At 1M tokens/day, you'd spend $10.50/month with Grok 4 Fast vs $150.00/month with Sonar Reasoning Pro - a $139.50 monthly difference.
Both models have comparable response speeds. For most applications, the latency difference is negligible.
When latency matters most: Interactive chatbots, IDE code completion, real-time translation, and user-facing applications where response time directly impacts experience. For batch processing, background summarization, or offline analysis, latency is less critical.
Code generation & review
Higher benchmark score (0/100) indicates stronger performance on coding tasks like generating functions, debugging, and refactoring
Customer support chatbot
Faster response time (speed score 0/100) is critical for user-facing chat. Grok 4 Fast also offers lower per-token costs for high-volume support
Long document analysis
Larger context window (2000K tokens) can process longer documents, contracts, and research papers in a single pass
Batch data extraction
Lower output pricing ($0.50/M) reduces costs when processing thousands of records daily
Creative writing & content
Higher overall composite score (83/100) correlates with better nuance, coherence, and style in long-form content
Image understanding & OCR
Supports vision input - can analyze screenshots, diagrams, photos, and scanned documents directly
Grok 4 Fast clearly outperforms Sonar Reasoning Pro with a significant 21.800000000000004-point lead. For most general use cases, Grok 4 Fast is the stronger choice. However, Sonar Reasoning Pro may still excel in niche scenarios.
Best for Quality
Grok 4 Fast
Marginally better benchmark scores; both are excellent
Best for Cost
Grok 4 Fast
93% lower pricing; better value at scale
Best for Reliability
Grok 4 Fast
Higher uptime and faster response speeds
Best for Prototyping
Grok 4 Fast
Stronger community support and better developer experience
Best for Production
Grok 4 Fast
Wider enterprise adoption and proven at scale
by xAI
| Capability | Grok 4 Fast | Sonar Reasoning Pro |
|---|---|---|
| Vision (Image Input) | ||
| Function Callingdiffers | ||
| Streaming | ||
| JSON Modediffers | ||
| Reasoning | ||
| Web Search | ||
| Image Output |
xAI
Perplexity
Grok 4 Fast saves you $12.24/month
That's 93% cheaper than Sonar Reasoning Pro at 1,000 tokens/request and 100 requests/day.
Assumes 60% input / 40% output token ratio per request. Actual costs may vary based on your usage pattern.
| Parameter | Grok 4 Fast | Sonar Reasoning Pro |
|---|---|---|
| Context Window | 2M | 128K |
| Max Output Tokens | 30,000 | -- |
| Open Source | No | No |
| Created | Sep 19, 2025 | Mar 7, 2025 |
Grok 4 Fast scores 83/100 (rank #52) compared to Sonar Reasoning Pro's 62/100 (rank #215), giving it a 22-point advantage. Grok 4 Fast is the stronger overall choice, though Sonar Reasoning Pro may excel in specific areas like certain benchmarks.
Grok 4 Fast is ranked #52 and Sonar Reasoning Pro is ranked #215 out of 290+ AI models. Rankings use a composite score combining benchmark performance (25%), pricing (25%), context window (15%), recency (15%), output capacity (10%), and versatility (10%). Scores update hourly.
Grok 4 Fast is cheaper at $0.50/M output tokens vs Sonar Reasoning Pro's $8.00/M output tokens - 16.0x more expensive. Input token pricing: Grok 4 Fast at $0.20/M vs Sonar Reasoning Pro at $2.00/M.
Grok 4 Fast has a larger context window of 2,000,000 tokens compared to Sonar Reasoning Pro's 128,000 tokens. A larger context window means the model can process longer documents and conversations.