xAI's real-time-first agentic model against OpenAI's reasoning flagship. Both are current frontier models as of September 2026 — here is a research-based comparison of their benchmarks, pricing, and where each one wins.
by OpenAI
Winnerby xAI
ChatGPT (GPT-6 Astra) leads on raw reasoning and coding, while Grok 4.6 wins on real-time data and price. This is a research-based analysis of published benchmarks, vendor pricing, and community feedback as of September 2026. GPT-6 Astra (released Sep 3, 2026) scores 99.9% on ARC-AGI-3, 74.1% on DeepSWE v1.1, and is the first critical-level cyber model at 100% on ExploitBench. It also offers a 1.05M token context window. Grok 4.6 (released Aug 12, 2026) is a 1.5T MoE model with a 500K token context, built for long-running agentic work, and it has native real-time X/Twitter data access. Grok 4.6 is dramatically cheaper at $2 input / $6 output per 1M tokens against GPT-6 Astra's $10 / $50. Grok 4.6 wins on live data and cost. Its first-party X firehose gives it a structural edge for anything that depends on what was said in the last 48 hours, and its price point makes it the default for high-volume batch work.
We evaluated both models across three task categories — live information retrieval, code refactoring, and long-document retrieval — using published benchmarks, vendor-published results, and community feedback from developers who ran these scenarios in production. We did not run hands-on tests ourselves; this is a research-based synthesis of reported outcomes. Task 3's 40-page document scenario is drawn from publicly shared retrieval test reports so retrieval accuracy is what is compared, not search.
| Metric | ChatGPT (GPT-6 Astra) | Grok 4.6 |
|---|---|---|
| Real-time social data access | Via search / browsing only | Native X firehose ✓ |
| ARC-AGI-3 (reasoning benchmark) | 99.9% ✓ | Not published as a headline figure |
| DeepSWE v1.1 (coding benchmark) | 74.1% ✓ | Not published as a headline figure |
| ExploitBench (cyber capability) | 100% (critical-level) ✓ | Not published as a headline figure |
| Context window | 1.05M tokens ✓ | 500K tokens |
| Architecture | Frontier reasoning model | 1.5T MoE, agentic-optimised ✓ |
| API price per 1M tokens (in / out) | $10.00 / $50.00 | $2.00 / $6.00 ✓ |
| Built for long-running agentic work | Strong general agent support | Explicit design goal ✓ |
| Winner by category | 🏆 GPT-6 Astra (reasoning, code, context) | 🏆 Grok 4.6 (real-time data, price, agentic) |
Side-by-side breakdown across key categories
| Feature | ChatGPT (GPT-6 Astra) | Grok 4.6 | Winner |
|---|---|---|---|
| Context window | 1.05M tokens | 500K tokens | ChatGPT (GPT-6 Astra) |
| First-party real-time social data | Via search / browsing only | Native X firehose | Grok 4.6 |
| Live breaking-change latency (reported) | Same day, ~2 browse passes | Hours after publication, first pass | Grok 4.6 |
| ARC-AGI-3 (vendor-published) | 99.9% (OpenAI) | Not published as headline | ChatGPT (GPT-6 Astra) |
| DeepSWE v1.1 (vendor-published) | 74.1% (OpenAI) | Not published as headline | ChatGPT (GPT-6 Astra) |
| ExploitBench (vendor-published) | 100% critical-level (OpenAI) | Not published as headline | ChatGPT (GPT-6 Astra) |
| OSWorld 2.0 (vendor-published) | 72.6% (OpenAI) | Not published as headline | ChatGPT (GPT-6 Astra) |
| Long-document retrieval (community reports) | Near-perfect clause recall | Solid, not class-leading | ChatGPT (GPT-6 Astra) |
| API price per 1M tokens (in / out) | $10.00 / $50.00 | $2.00 / $6.00 | Grok 4.6 |
| Cheapest paid consumer tier | $20/mo Plus | $30/mo SuperGrok | ChatGPT (GPT-6 Astra) |
| Agent / coding toolchain | Codex, CLI, repo connectors | API and MCP integrations, thinner tooling | ChatGPT (GPT-6 Astra) |
| Built for long-running agentic work | Strong general agent support | Explicit design goal (1.5T MoE) | Grok 4.6 |
| Conversational tone | Structured, more cautious | Looser, fewer refusals | Grok 4.6 |
| Tier | ChatGPT (GPT-6 Astra) | Grok 4.6 |
|---|---|---|
| Free | Yes — GPT-6 Astra available with daily caps | Yes — x.com and grok.com with message limits |
| Entry paid | $20/mo Plus — GPT-6 Astra plus the GPT-5.6 line in the picker | $30/mo SuperGrok — higher limits and heavier modes |
| Top consumer tier | $200/mo Pro | ~$40/mo X Premium+ bundles Grok with the platform; SuperGrok Heavy is a separate premium tier |
| API (per 1M tokens) | $10.00 in / $50.00 out | $2.00 in / $6.00 out |
| Cheapest way to use it | Free tier | Free tier on X, or SuperGrok at $30/mo |
All figures are the vendors’ published consumer and API rates as checked on the openai.com and x.ai pricing pages in September 2026; they move often, so confirm on the vendor’s own page before you buy. At the API layer Grok 4.6 costs roughly 20% of GPT-6 Astra per input token and about 12% per output token — a much larger gap than the consumer subscription difference of $10 a month. Our method is documented on the How We Evaluate page.
This is a split by speciality, not by overall quality: pick GPT-6 Astra for deep reasoning, coding, and long documents; pick Grok 4.6 for real-time X data, long-running agentic work, and cost. Both are current frontier models as of September 2026, and the right choice depends on what your work actually demands.
99.9% on ARC-AGI-3, 74.1% on DeepSWE v1.1, and the first critical-level cyber model at 100% on ExploitBench. For coding, document work and anything that needs deep reasoning, this is the rational default.
Native X firehose surfaces breaking changes from maintainer posts within hours, in one pass. If your answer depends on the last 48 hours, its first-party X feed is a real structural advantage over browsing-based alternatives.
$2/$6 per 1M tokens against GPT-6 Astra's $10/$50. For high-volume batch work the per-token gap dominates the total cost long before model quality becomes the deciding factor.
1.05M context against 500K, with community reports of near-perfect long-document retrieval. Retrieval accuracy, not raw context size, is what matters — and GPT-6 Astra leads on both counts.
GPT-6 Astra leads on reasoning, coding, and context; Grok 4.6 wins on real-time X data and price. Both have free tiers, so you can settle this yourself in an afternoon.
Still deciding? Check out these related comparisons and best-of guides.