GPT-5.1 Codex High vs Kimi K2-Thinking-0905: Specs & Benchmark Comparison

CharacteristicGPT-5.1 Codex HighKimi K2-Thinking-0905
CompanyOpenAIMoonshot AI
Release DateNovember 11, 2025September 4, 2025
Parameters1.0T
MultimodalYesNo
Context (input)400K262K
Context (output)128K66K
Input Price / 1M$1.25$0.60
Output Price / 1M$10.00$2.40
Average Score1.00.9
Benchmarks
AIME 20251.01.0

Visual Benchmark Comparison

GPT-5.1 Codex High
Kimi K2-Thinking-0905
AIME 20251.0 vs 1.0
1.0
1.0

Verdict

GPT-5.1 Codex High leads in 2 out of 4 comparison categories.

Overall Performance

Both models show comparable average scores: GPT-5.1 Codex High — 1.0, Kimi K2-Thinking-0905 — 0.9.

API Cost

Kimi K2-Thinking-0905 is 3.8x cheaper: input $0.60/1M vs $1.25/1M tokens.

Context Window

GPT-5.1 Codex High supports a larger context: 400K vs 262K tokens.

Recency

GPT-5.1 Codex High is newer: released 11/11/2025 vs 9/4/2025.

More About These Models

Related Comparisons

The GPT-5.1 Codex High and Kimi K2-Thinking-0905 comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the GPT-5.1 Codex High or Kimi K2-Thinking-0905 page. See also the complete list of AI model comparisons.