Updated March 26, 2026· Based on independent benchmark data
Grok 4.20 Beta 0309 (Reasoning) and GPT-5.1 (high) are virtually tied on intelligence (48.5 vs 47.7). GPT-5.1 (high) is 1.6x cheaper at $1.25/1M tokens vs $2.00/1M. For speed, Grok 4.20 Beta 0309 (Reasoning) wins at 246 tok/s vs 92 tok/s.
| Metric | Grok 4.20 Beta 0309 (Reasoning) | GPT-5.1 (high) |
|---|---|---|
| Intelligence Score | 48.5 | 47.7 |
| Coding Score | 42.2 | 44.7 |
| Math Score | N/A | 94.0 |
| Speed (tok/s) | 246 tok/s | 92 tok/s |
| Latency (TTFT) | 11.75s | 39.04s |
| Input Price / 1M tokens | $2.00 | $1.25 |
| Output Price / 1M tokens | $6.00 | $10 |
| Context Window | N/A |
Grok 4.20 Beta 0309 (Reasoning) and GPT-5.1 (high) perform similarly on overall intelligence, scoring 48.5 and 47.7 respectively. For coding tasks, GPT-5.1 (high) has the edge with a coding score of 44.7 vs 42.2.
Grok 4.20 Beta 0309 (Reasoning) generates output significantly faster at 246 tok/s compared to GPT-5.1 (high)'s 92 tok/s, making it 2.7x faster for streaming responses. Time to first token is 11.75s for Grok 4.20 Beta 0309 (Reasoning) vs 39.04s for GPT-5.1 (high), which affects perceived responsiveness in interactive applications.
GPT-5.1 (high) is more affordable at $1.25/1M input tokens ($10/1M output), while Grok 4.20 Beta 0309 (Reasoning) costs $2.00/1M input ($6.00/1M output). For a typical workload of 100 requests per day at 2,000 tokens each, Grok 4.20 Beta 0309 (Reasoning) would cost approximately $12.00/month vs $7.50/month for GPT-5.1 (high) in input costs alone.
Choose Grok 4.20 Beta 0309 (Reasoning) when you need faster output (246 tok/s). Choose GPT-5.1 (high) when you need stronger coding performance (44.7), lower cost.
GPT-5.1 (high) scores higher on coding benchmarks (44.7 vs 42.2), making it the better choice for programming tasks.
GPT-5.1 (high) is cheaper at $1.25/1M input tokens vs $2.00/1M for Grok 4.20 Beta 0309 (Reasoning).
Grok 4.20 Beta 0309 (Reasoning) is faster, producing output at 246 tok/s compared to GPT-5.1 (high)'s 92 tok/s.
No, Grok 4.20 Beta 0309 (Reasoning) does not support image input. Neither model supports image input.
Data last synced: March 26, 2026
| N/A |
| Max Output Tokens | N/A | N/A |
| Input Modalities | Text | Text |
| Output Modalities | Text | Text |
| Free Tier | No | No |
Both models perform similarly on intelligence benchmarks. Choose based on specific needs: pricing, speed, context window, or provider ecosystem.