GPT-5.6 Sol vs Grok 4.20 0309
Head-to-head specifications
| Metric | GPT-5.6 Sol | Grok 4.20 0309 | Difference |
|---|---|---|---|
| Intelligence Index | 59.0 | 27.0 | +118.5% |
| Context window | 1M tokens | 2M tokens | — |
| Blended price ($/1M tokens) | $1.54 | $0.72 | +113.9% |
| Access | Proprietary API | Proprietary API | — |
- GPT-5.6 Sol leads overall capability (Intelligence Index 59.0 vs 27.0).
- Grok 4.20 0309 is the cheaper model to run at $0.72/1M blended tokens — about 2.1× cheaper.
- Grok 4.20 0309 offers the larger context window (2M tokens), useful for long documents and codebases.
Verdict: GPT-5.6 Sol or Grok 4.20 0309?
GPT-5.6 Sol advantages
- General intelligence (+54%)
Grok 4.20 0309 advantages
- Context window (+50%)
- Affordability (+53%)
Which should you choose?
- Choose the GPT-5.6 Sol if you need the strongest overall reasoning and accuracy.
- Choose the Grok 4.20 0309 if you work with long documents or large codebases.
Value for money
GPT-5.6 Sol offers more intelligence per dollar (1.0× the Intelligence-Index-per-cost of the alternative), making it the stronger value for high-volume use.
GPT-5.6 Sol vs Grok 4.20 0309: which should you choose?
GPT-5.6 Sol — OpenAI multimodal model with an Intelligence Index of 59, a 1M-token context window and a blended price of $1.54/1M tokens.
Grok 4.20 0309 — xAI multimodal model with an Intelligence Index of 27, a 2M-token context window and a blended price of $0.72/1M tokens.
GPT-5.6 Sol vs Grok 4.20 0309: GPT-5.6 Sol scores higher on the Intelligence Index. GPT-5.6 Sol leads overall capability (Intelligence Index 59.0 vs 27.0). Grok 4.20 0309 is the cheaper model to run at $0.72/1M blended tokens — about 2.1× cheaper.
Capability: intelligence, coding and agentic work
On the composite Intelligence Index the GPT-5.6 Sol scores 59.0 versus 27.0. Composite indices summarize many evaluations, but always test on your own workload before committing.
Context window and speed
The Grok 4.20 0309 accepts up to 2 million tokens per request, which sets how much documentation, transcript or code it can reason over at once.
Pricing and access
At blended per-token rates, Grok 4.20 0309 is the cheaper model to run ($0.72 vs $1.54 per 1M tokens). GPT-5.6 Sol is proprietary api and Grok 4.20 0309 is proprietary api. Open-weight models can be self-hosted, trading per-call cost for infrastructure you manage; for production also weigh rate limits, throughput and data-residency requirements.
The verdict
Both are credible choices in the ai model comparison space; the specification table above lays out every metric so you can weigh the trade-offs that matter to you. Pick the one whose strengths line up with how you will actually use it.
Frequently asked questions
Is the GPT-5.6 Sol better than the Grok 4.20 0309?
These two are closely matched — the right pick comes down to which specific strengths you value and the price you actually pay. GPT-5.6 Sol leads overall capability (Intelligence Index 59.0 vs 27.0).
What is the main difference between the GPT-5.6 Sol and the Grok 4.20 0309?
GPT-5.6 Sol leads overall capability (Intelligence Index 59.0 vs 27.0). Grok 4.20 0309 is the cheaper model to run at $0.72/1M blended tokens — about 2.1× cheaper.
Which is better value?
GPT-5.6 Sol offers more intelligence per dollar (1.0× the Intelligence-Index-per-cost of the alternative), making it the stronger value for high-volume use.
Which should I choose?
Choose the GPT-5.6 Sol if you need the strongest overall reasoning and accuracy. Choose the Grok 4.20 0309 if you work with long documents or large codebases.
Methodology
Large language models are compared on independent leaderboard metrics: an Intelligence Index (a composite of reasoning and knowledge evaluations), Coding and Agentic indices where measured, community arena Elo, maximum context window, a blended API price per million tokens (weighted across cache-hit, input and output rates), and measured output speed in tokens per second. Where a model ships multiple reasoning-effort variants, we report its strongest variant. Benchmarks capture only part of real-world quality, which also depends on tool use, latency, safety and task fit — and this space moves quickly, so figures reflect the leaderboard snapshot on the page date.