GPT-6 Astra vs Solar Pro 4: Specs & Benchmark Comparison
GPT-6 Astra is developed by OpenAI, while Solar Pro 4 comes from Upstage. Solar Pro 4 was released in August 2026, and GPT-6 Astra followed a month later in September 2026.
The two models share 2 published benchmarks. GPT-6 Astra leads on 2 of them. The widest gaps are on BrowseComp, where GPT-6 Astra scores 91.5% against 49.2%; GPQA Diamond, where GPT-6 Astra scores 96.0% against 89.0%. Averaged across everything we track, GPT-6 Astra sits at 74.4% and Solar Pro 4 at 69.9%.
Solar Pro 4 is the cheaper API at $0.30 per million input tokens and $1.20 per million output tokens, roughly 33 times cheaper than GPT-6 Astra at $10 and $50. GPT-6 Astra takes the larger context window at 1M tokens, compared with 524K for Solar Pro 4. GPT-6 Astra accepts text and images as input, while Solar Pro 4 accepts text. On tooling, only GPT-6 Astra supports function calling and only GPT-6 Astra offers structured output.
| Characteristic | GPT-6 Astra | Solar Pro 4 |
|---|---|---|
| Company | OpenAI | Upstage |
| Release Date | September 4, 2026 | August 6, 2026 |
| Parameters | — | — |
| Multimodal | Yes | No |
| Context (input) | 1.1M | 524K |
| Context (output) | 128K | 131K |
| Input Price / 1M | $10.00 | $0.30 |
| Output Price / 1M | $50.00 | $1.20 |
| Average Score | 74.4% | 69.9% |
| Benchmarks | ||
| BrowseComp | 91.5% | 49.2% |
| GPQA Diamond | 96.0% | 89.0% |
Visual Benchmark Comparison
Verdict
GPT-6 Astra leads in 2 out of 4 comparison categories.
Both models show comparable average scores: GPT-6 Astra — 0.7, Solar Pro 4 — 0.7.
Solar Pro 4 is 40.0x cheaper: input $0.30/1M vs $10.00/1M tokens.
GPT-6 Astra supports a larger context: 1M vs 524K tokens.
GPT-6 Astra is newer: released 9/4/2026 vs 8/6/2026.
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Frequently Asked Questions
Which is better for coding — GPT-6 Astra or Solar Pro 4?
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Which has a larger context window — GPT-6 Astra or Solar Pro 4?
The GPT-6 Astra and Solar Pro 4 comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the GPT-6 Astra or Solar Pro 4 page. See also the complete list of AI model comparisons.