Compare AI models

Specifications
ParametersThe learned values that shape how a model responds. B means billion and T means trillion. For mixture-of-experts models, the total count is larger than the number active for each token. Parameter count alone does not measure quality.
—671B
Context windowHow much information the model can work with in one request, measured in tokens — pieces of words or other data. This includes your question, attachments, conversation and reply. Limits can vary by model variant and provider.
1M128k
API pricingUSD per 1M tokens · lower wins
Cheapest inputLowest input rate across every provider on OpenRouter, the lab included. The cheapest endpoint may run a quantised build or a shorter context — see "Available from" on the model page.
—$0.27SiliconFlow
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
—$1.00SiliconFlow
—$104SiliconFlow · fp8
Benchmarks
SWE-Bench VerifiedCoding — Real coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better.
93.9%68.4%
SWE-Bench MultilingualMultilingual coding — Like SWE-Bench, but the coding problems span many programming languages, not just one. Tests how broadly the AI can code. Higher is better.
87.3%57.8%
GPQA DiamondScience — Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better.
94.5%80.7%
Overview
CompanyAnthropicDeepSeek
Release dateApr 7 2026Sep 22 2025
AccessClosedOpen Weight
Model detailsView modelView model

Frequently asked questions

Claude Mythos Preview leads DeepSeek V3.1 Terminus on 3 of the 3 benchmarks they both report (SWE-Bench Verified, SWE-Bench Multilingual, GPQA Diamond). DeepSeek V3.1 Terminus shipped 197 days before Claude Mythos Preview, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Claude Mythos Preview) vs 128k (DeepSeek V3.1 Terminus). Claude Mythos Preview is closed, while DeepSeek V3.1 Terminus is open weight.

On SWE-Bench Verified, Claude Mythos Preview leads at 93.9% vs DeepSeek V3.1 Terminus at 68.4%. On SWE-Bench Multilingual, Claude Mythos Preview leads at 87.3% vs DeepSeek V3.1 Terminus at 57.8%. On GPQA Diamond, Claude Mythos Preview leads at 94.5% vs DeepSeek V3.1 Terminus at 80.7%.