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Claude 3.5 Sonnet vs DeepSeek V3.1 Terminus

2 vs 0 benchmarks won

Anthropic
Claude 3.5 Sonnet
DeepSeek
DeepSeek V3.1 Terminus
Overview
CompanyAnthropicDeepSeek
Release dateJun 20 2024Sep 22 2025
Model type
Open sourceNoYes
Specifications
Parameters
Context window
Benchmarks
Science reasoning
GPQA Diamond
59.4%
Software engineering
SWE-Bench Verified
33.4%
Multimodal understanding
MMMU
Timeline
Release gapClaude 3.5 Sonnet shipped 459 days before DeepSeek V3.1 Terminus

Which is better: Claude 3.5 Sonnet or DeepSeek V3.1 Terminus?

Claude 3.5 Sonnet leads DeepSeek V3.1 Terminus on 2 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). Claude 3.5 Sonnet shipped 459 days before DeepSeek V3.1 Terminus, so benchmark comparisons should account for the intervening progress.

DeepSeek V3.1 Terminus is an open-source / open-weight model; Claude 3.5 Sonnet is proprietary.

Direct benchmark comparisons are unavailable — at least one of these models has not published scores on GPQA Diamond, SWE-Bench Verified, or MMMU.

Frequently asked questions

When was Claude 3.5 Sonnet released?
Claude 3.5 Sonnet was released by Anthropic on Jun 20 2024.
When was DeepSeek V3.1 Terminus released?
DeepSeek V3.1 Terminus was released by DeepSeek on Sep 22 2025.
Is Claude 3.5 Sonnet or DeepSeek V3.1 Terminus open source?
DeepSeek V3.1 Terminus is an open-source / open-weight model released by DeepSeek. Claude 3.5 Sonnet is a proprietary model released by Anthropic.

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