When was DeepSeek-V4-Flash released?

DeepSeek-V4-Flash was released by DeepSeek on Apr 24 2026.

When was GPT-5.5 released?

GPT-5.5 was released by OpenAI on Apr 23 2026.

Which is better on GPQA Diamond, DeepSeek-V4-Flash or GPT-5.5?

GPT-5.5 scores higher on GPQA Diamond — DeepSeek-V4-Flash 88.1% vs GPT-5.5 93.6%.

Is DeepSeek-V4-Flash or GPT-5.5 open source?

DeepSeek-V4-Flash is an open-source / open-weight model released by DeepSeek. GPT-5.5 is a proprietary model released by OpenAI.

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Latest Release

DeepSeek-V4-Pro

Apr 24 2026

Home/Compare/DeepSeek-V4-Flash vs GPT-5.5

DeepSeek-V4-Flash vs GPT-5.5

0 vs 1 benchmarks won

	DeepSeek DeepSeek-V4-Flash	OpenAI GPT-5.5
Overview
Company	DeepSeek	OpenAI
Release date	Apr 24 2026	Apr 23 2026
Model type	—	—
Open source	Yes	No
Specifications
Parameters	—	—
Context window	—	—
Benchmarks
Science reasoning GPQA Diamond	88.1%	93.6%
Software engineering SWE-Bench Verified	—	—
Multimodal understanding MMMU	—	—
Timeline
Release gap	GPT-5.5 shipped 1 days before DeepSeek-V4-Flash

Which is better: DeepSeek-V4-Flash or GPT-5.5?

GPT-5.5 leads DeepSeek-V4-Flash on 1 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). GPT-5.5 shipped 1 days before DeepSeek-V4-Flash, so benchmark comparisons should account for the intervening progress.

DeepSeek-V4-Flash is an open-source / open-weight model; GPT-5.5 is proprietary.

On GPQA Diamond, GPT-5.5 scores 93.6%, 5.5 points above DeepSeek-V4-Flash at 88.1%.

Frequently asked questions

When was DeepSeek-V4-Flash released?: DeepSeek-V4-Flash was released by DeepSeek on Apr 24 2026.
When was GPT-5.5 released?: GPT-5.5 was released by OpenAI on Apr 23 2026.
Which is better on GPQA Diamond, DeepSeek-V4-Flash or GPT-5.5?: GPT-5.5 scores higher on GPQA Diamond — DeepSeek-V4-Flash 88.1% vs GPT-5.5 93.6%.
Is DeepSeek-V4-Flash or GPT-5.5 open source?: DeepSeek-V4-Flash is an open-source / open-weight model released by DeepSeek. GPT-5.5 is a proprietary model released by OpenAI.