GPT-6: Astra vs GPT-5.6 Sol

GPT-6: Astra costs $10 per 1M input tokens, 2.5x GPT-5.6 Sol's $4. On the independent Artificial Analysis Intelligence Index the two tie at 61. Astra is roughly 70% more token-efficient on coding and cuts max-effort hallucination rate from 92% to 51%, but GDPval-AA v2 regressed about 80 Elo against Sol even as AA-Briefcase gained about 80 Elo — a genuine capability trade, not a uniform upgrade.

Last verified 5 September 2026.

Stated negative: tied on Intelligence Index at 2.5x the price

GPT-6: Astra and GPT-5.6 Sol score identically at 61 on the independent Artificial Analysis Intelligence Index. Astra's input price is $10 per 1M tokens against Sol's $4, a 2.5x premium for a tied composite score. Any workload that is not sensitive to Astra's specific gains (coding efficiency, hallucination rate, long context) should default to Sol on cost alone.

Pricing, including the long-context tiers

Sol's long-context pricing above 272,000 input tokens is a published, live-fetchable object on the OneInfer catalog. Astra's long-context surcharge above the same 272,000-token threshold is a published multiplier rather than a separate live tier: 2x the input rate and 1.5x the output rate.

Dimension	GPT-6: Astra	GPT-5.6 Sol
Input $/1M (standard)	$10.00	$4.00
Output $/1M (standard)	$50.00	$20.00
Cached input $/1M	$1.00	$0.50
Above 272K input tokens	2x input, 1.5x output (surcharge)	$8.00 input / $30.00 output / $0.80 cached (published tier)
Context window	1,050,000	not published at this size

Where Astra genuinely improves on Sol

Three OpenAI/Artificial-Analysis-reported deltas favour Astra directly: hallucination rate at maximum reasoning effort improved from 92% to 51%; Astra is roughly 70% more token-efficient than Sol on coding tasks, which offsets some of the per-token price gap on agentic coding workloads; and Astra completes computer-use tasks roughly 47% faster than Sol.

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Where Astra regresses against Sol

GDPval-AA v2 — a professional-workflow evaluation — regressed by roughly 80 Elo for Astra relative to Sol, even as Astra gained roughly 80 Elo on the AA-Briefcase evaluation. State this as a genuine trade rather than a uniform upgrade: Astra is not strictly better than its own predecessor on every axis Artificial Analysis tracks.

Should you upgrade from Sol to Astra?

Upgrade if your workload is long-context (above 272K tokens, where Astra's ceiling is meaningfully higher), coding-token-efficiency sensitive, or hallucination-rate sensitive at maximum effort. Stay on Sol if your workload resembles the GDPval-AA v2 professional-document profile, or if the tied Intelligence Index means the 2.5x price premium buys nothing measurable for your use case.

Frequently asked questions

Is GPT-6: Astra better than GPT-5.6 Sol?

It depends on the axis. The two tie at 61 on the independent Artificial Analysis Intelligence Index despite Astra costing 2.5x more per input token. Astra is about 70% more token-efficient on coding and cuts max-effort hallucination rate from 92% to 51%, but it regressed roughly 80 Elo on GDPval-AA v2 relative to Sol even as it gained roughly 80 Elo on AA-Briefcase. This is a capability trade, not a uniform upgrade.

How much more expensive is GPT-6: Astra than GPT-5.6 Sol?

GPT-6: Astra costs $10 per 1M input tokens against $4 for GPT-5.6 Sol at standard pricing, a 2.5x premium. Output is $50 against $20, also 2.5x. Above the shared 272,000-token threshold, Sol moves to a published tier ($8/$30/$0.80 cached) while Astra applies a 2x input / 1.5x output surcharge on its own base rate.