AI Model Release Tracker - Timeline of Major AI Models from 2022-2026

Mistral Medium 3.5 vs o1-preview

Mistral
Mistral Medium 3.5
OpenAI
o1-preview
Overview
CompanyMistralOpenAI
Release dateApr 29 2026Sep 12 2024
Model type
Open sourceYesNo
Specifications
Parameters
128B
Context window
256k
Benchmarks
Coding
SWE-Bench Verified
77.6%
Timeline
Release gapo1-preview shipped 594 days before Mistral Medium 3.5

Which is better: Mistral Medium 3.5 or o1-preview?

Mistral Medium 3.5 and o1-preview don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. o1-preview shipped 594 days before Mistral Medium 3.5, so benchmark comparisons should account for the intervening progress.

Mistral Medium 3.5 is an open-source / open-weight model; o1-preview is proprietary.

Direct benchmark comparisons are unavailable — Mistral Medium 3.5 and o1-preview don't publish scores on any of the same benchmarks.

Frequently asked questions

When was Mistral Medium 3.5 released?
Mistral Medium 3.5 was released by Mistral on Apr 29 2026.
When was o1-preview released?
o1-preview was released by OpenAI on Sep 12 2024.
Is Mistral Medium 3.5 or o1-preview open source?
Mistral Medium 3.5 is an open-source / open-weight model released by Mistral. o1-preview is a proprietary model released by OpenAI.

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