Quality
Known Good Index and the capability indices, side by side
Each index is min-max normalised across tracked models and scaled 0–100 from published evaluations. We do not run these evaluations.
| Metric | claude-sonnet-4-5-20250929 | gpt-5.5-pre-release |
|---|---|---|
| Known Good Index | 59 | 98 |
| Coding Index | 61 | — |
| Mathematics Index | 89 | 100 |
| Science Index | 84 | 99 |
| Reasoning Index | 48 | — |
| Agentic Index | 61 | 94 |
| Openness Index | 5 | 5 |
Quality Breakdown
Every evaluation both models report a published score for
Bar = claude-sonnet-4-5-20250929 · marker = gpt-5.5-pre-release · scores ingested from Epoch AI (CC-BY 4.0)
Right-hand figures read claude-sonnet-4-5-20250929 / gpt-5.5-pre-release. claude-sonnet-4-5-20250929 leads on 0 of 3, gpt-5.5-pre-release on 3.
Arena Elo
Human preference rating from blind pairwise votes
Elo from blind pairwise votes, ingested from Arena. Higher is better.
| Metric | claude-sonnet-4-5-20250929 | gpt-5.5-pre-release |
|---|---|---|
| Text Arena | 1,438 | — |
| Text Arena (style controlled) | 1,455 | — |
Price & Cost
Published API pricing by token type
USD per 1M tokens. Blended is a 3:1 input:output mix. Live from OpenRouter, cross-checked against models.dev. Lower is better.
| Metric | claude-sonnet-4-5-20250929 | gpt-5.5-pre-release |
|---|---|---|
| Input $/1M | — | — |
| Output $/1M | — | — |
| Blended $/1M | — | — |
| Cache read $/1M | — | — |
Context Window
Maximum input accepted and maximum output emitted
Provider-declared limits, from metadata via models.dev and OpenRouter. Higher is better.
| Metric | claude-sonnet-4-5-20250929 | gpt-5.5-pre-release |
|---|---|---|
| Context window | — | — |
| Max output tokens | — | — |
Speed & Latency
Median throughput and time to first token across hosting providers
Medians across all tracked providers, derived from OpenRouter endpoint telemetry.
| Metric | claude-sonnet-4-5-20250929 | gpt-5.5-pre-release |
|---|---|---|
| Output tokens/s | — | — |
| Time to first token | — | — |
Providers
Which hosts serve each model, and at what price and speed
No hosting providers are currently tracked for either model.