Claude 4.5 Sonnet (Reasoning) vs Claude Opus 5.5 (Xhigh, Default Fallback)
Which is better for the money: Claude 4.5 Sonnet (Reasoning) by Anthropic or Claude Opus 5.5 (Xhigh, Default Fallback) by Anthropic? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-24.
Trade-off
Verdict
Depends on your budget
Claude Opus 5.5 (Xhigh, Default Fallbac… scores 35.3 points higher (56.0 vs 20.7) but costs 2.7× as much to run the benchmark ($4057 vs $1501; flagship vs premium cost classes). Pick Claude Opus 5.5 (Xhigh, Default Fallbac… when the extra intelligence is worth the premium, otherwise Claude 4.5 Sonnet (Reasoning).
| Metric | Claude 4.5 Sonnet (Reasoning) | Claude Opus 5.5 (Xhigh, Default Fallback) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 20.7 | 56.0 | +170.5% Claude Opus 5.5 (Xhig… is 2.7× more intelligent |
| Total AA cost (lower is better) | $1,501.22 | $4,056.65 | +170.2% Claude Opus 5.5 (Xhig… is 2.7× more expensive |
| End-to-end time (lower is better) | 20.84s | 123.06s | +490.5% Claude Opus 5.5 (Xhig… is 490.5% slower |
| Price per 1M tokens (in / out) | $3.00 / $15.0 | $4.00 / $20.0 | |
| Input modalities | Text, Image | Text, Image |
Claude Opus 5.5 (Xhigh, Default Fallback) vs Claude 4.5 Sonnet (Reasoning): 170.5% more intelligence, 170.2% more cost to run the AA benchmark, and 490.5% slower end-to-end.
Today's Pareto frontier
Against the frontier
- Claude 4.5 Sonnet (Reasoning) is off the frontier: at the same or lower cost, GPT-6.1 Sol (Max) scores 51.80 for $1082.
- Claude Opus 5.5 (Xhigh, Default Fallback) is on today's frontier: nothing is both smarter and cheaper.
Claude 4.5 Sonnet (Reasoning)Claude Opus 5.5 (Xhigh, Default Fallback)Today's Pareto frontierEvery other model
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