Compare · ModelsLive · 2 picked · head to head
GPT-5.5 Pro vs Claude Mythos Preview
Side by side · benchmarks, pricing, and signals you can act on.
Winner summary
Claude Mythos Preview wins on 1/1 benchmarks
Claude Mythos Preview wins 1 of 1 shared benchmarks. Leads in knowledge.
Category leads
knowledge·Claude Mythos Preview
Hype vs Reality
Attention vs performance
GPT-5.5 Pro
#1 by perf·no signal
Claude Mythos Preview
#4 by perf·#2 by attention
Vendor risk
Who is behind the model
OpenAI
$840.0B·Tier 1
Anthropic
$380.0B·Tier 1
Head to head
1 benchmark · 2 models
GPT-5.5 ProClaude Mythos Preview
GPQA diamond
Claude Mythos Preview leads by +0.3
Graduate-Level Google-Proof QA (Diamond set) · expert-crafted questions in physics, biology, and chemistry that are difficult even for domain PhDs.
GPT-5.5 Pro
94.2
Claude Mythos Preview
94.5
Full benchmark table
| Benchmark | GPT-5.5 Pro | Claude Mythos Preview |
|---|---|---|
GPQA diamond Graduate-Level Google-Proof QA (Diamond set) · expert-crafted questions in physics, biology, and chemistry that are difficult even for domain PhDs. | 94.2 | 94.5 |
Pricing · per 1M tokens · projected $/mo at 10M tokens
| Model | Input | Output | Context | Projected $/mo |
|---|---|---|---|---|
| $30.00 | $180.00 | 400K tokens (~200 books) | $675.00 | |
| — | — | 1.0M tokens (~500 books) | — |