Head-to-head comparison across 4benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
GPT-5.4
89
Kimi K2.5 (Reasoning)
76
Verified leaderboard positions: GPT-5.4 #16 · Kimi K2.5 (Reasoning) unranked
Pick GPT-5.4 if you want the stronger benchmark profile. Kimi K2.5 (Reasoning) only becomes the better choice if knowledge is the priority or you want the cheaper token bill.
Agentic
+22.4 difference
Coding
+19.1 difference
Knowledge
+21.2 difference
Multimodal
+5.8 difference
GPT-5.4
Kimi K2.5 (Reasoning)
$2.5 / $15
$0.6 / $3
74 t/s
N/A
151.79s
N/A
1.05M
128K
Pick GPT-5.4 if you want the stronger benchmark profile. Kimi K2.5 (Reasoning) only becomes the better choice if knowledge is the priority or you want the cheaper token bill.
GPT-5.4 is clearly ahead on the provisional aggregate, 89 to 76. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.4's sharpest advantage is in agentic, where it averages 77 against 54.6. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 75.1% to 50.8%. Kimi K2.5 (Reasoning) does hit back in knowledge, so the answer changes if that is the part of the workload you care about most.
GPT-5.4 is also the more expensive model on tokens at $2.50 input / $15.00 output per 1M tokens, versus $0.60 input / $3.00 output per 1M tokens for Kimi K2.5 (Reasoning). That is roughly 5.0x on output cost alone. GPT-5.4 gives you the larger context window at 1.05M, compared with 128K for Kimi K2.5 (Reasoning).
GPT-5.4 is ahead on BenchLM's provisional leaderboard, 89 to 76. The biggest single separator in this matchup is Terminal-Bench 2.0, where the scores are 75.1% and 50.8%.
Kimi K2.5 (Reasoning) has the edge for knowledge tasks in this comparison, averaging 87.3 versus 66.1. Inside this category, AA-Omniscience Hallucination Rate is the benchmark that creates the most daylight between them.
Kimi K2.5 (Reasoning) has the edge for coding in this comparison, averaging 76.8 versus 57.7. Inside this category, Vibe Code Bench is the benchmark that creates the most daylight between them.
GPT-5.4 has the edge for agentic tasks in this comparison, averaging 77 versus 54.6. Inside this category, GDPval-AA is the benchmark that creates the most daylight between them.
Kimi K2.5 (Reasoning) has the edge for multimodal and grounded tasks in this comparison, averaging 78.5 versus 72.7. Inside this category, AA-MMMU-Pro is the benchmark that creates the most daylight between them.
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