When was Kimi K2 (0905) released?

Kimi K2 (0905) was released by Moonshot AI on Sep 5 2025.

When was GPT-5.4 released?

GPT-5.4 was released by OpenAI on Mar 5 2026.

Which is better on GPQA Diamond, Kimi K2 (0905) or GPT-5.4?

GPT-5.4 scores higher on GPQA Diamond — Kimi K2 (0905) 75.1% vs GPT-5.4 92.8%.

Is Kimi K2 (0905) or GPT-5.4 open source?

Kimi K2 (0905) is an open-source / open-weight model released by Moonshot AI. GPT-5.4 is a proprietary model released by OpenAI.

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Home/Compare/Kimi K2 (0905) vs GPT-5.4

Kimi K2 (0905) vs GPT-5.4

1 vs 1 benchmarks won

	Moonshot AI Kimi K2 (0905)	OpenAI GPT-5.4
Overview
Company	Moonshot AI	OpenAI
Release date	Sep 5 2025	Mar 5 2026
Model type	—	—
Open source	Yes	No
Specifications
Parameters	1T	—
Context window	256k	—
Benchmarks
Science reasoning GPQA Diamond	75.1%	92.8%
Software engineering SWE-Bench Verified	65.8%	—
Multimodal understanding MMMU	—	—
Timeline
Release gap	Kimi K2 (0905) shipped 181 days before GPT-5.4

Which is better: Kimi K2 (0905) or GPT-5.4?

Kimi K2 (0905) and GPT-5.4 are evenly matched across the benchmarks they both publish. Kimi K2 (0905) shipped 181 days before GPT-5.4, so benchmark comparisons should account for the intervening progress.

Kimi K2 (0905) is an open-source / open-weight model; GPT-5.4 is proprietary.

On GPQA Diamond, GPT-5.4 scores 92.8%, 17.7 points above Kimi K2 (0905) at 75.1%.

Frequently asked questions

When was Kimi K2 (0905) released?: Kimi K2 (0905) was released by Moonshot AI on Sep 5 2025.
When was GPT-5.4 released?: GPT-5.4 was released by OpenAI on Mar 5 2026.
Which is better on GPQA Diamond, Kimi K2 (0905) or GPT-5.4?: GPT-5.4 scores higher on GPQA Diamond — Kimi K2 (0905) 75.1% vs GPT-5.4 92.8%.
Is Kimi K2 (0905) or GPT-5.4 open source?: Kimi K2 (0905) is an open-source / open-weight model released by Moonshot AI. GPT-5.4 is a proprietary model released by OpenAI.