Side-by-side benchmark comparison across knowledge, coding, math, and reasoning.
Kimi K2.5 is clearly ahead on the aggregate, 68 to 51. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Kimi K2.5's sharpest advantage is in coding, where it averages 49.3 against 41. The single biggest benchmark swing on the page is MMLU, 77 to 91.8. o1 does hit back in knowledge, so the answer changes if that is the part of the workload you care about most.
o1 is also the more expensive model on tokens at $15.00 input / $60.00 output per 1M tokens, versus $0.50 input / $2.80 output per 1M tokens for Kimi K2.5. That is roughly 21.4x on output cost alone. o1 is the reasoning model in the pair, while Kimi K2.5 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. o1 gives you the larger context window at 200K, compared with 128K for Kimi K2.5.
Pick Kimi K2.5 if you want the stronger benchmark profile. o1 only becomes the better choice if knowledge is the priority or you need the larger 200K context window.
Kimi K2.5
64
o1
83.8
Kimi K2.5
49.3
o1
41
Kimi K2.5
76.8
o1
74.3
Kimi K2.5
85
o1
92.2
Kimi K2.5 is ahead overall, 68 to 51. The biggest single separator in this matchup is MMLU, where the scores are 77 and 91.8.
o1 has the edge for knowledge tasks in this comparison, averaging 83.8 versus 64. Inside this category, MMLU is the benchmark that creates the most daylight between them.
Kimi K2.5 has the edge for coding in this comparison, averaging 49.3 versus 41. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.
Kimi K2.5 has the edge for math in this comparison, averaging 76.8 versus 74.3. Inside this category, AIME 2024 is the benchmark that creates the most daylight between them.
o1 has the edge for instruction following in this comparison, averaging 92.2 versus 85. Inside this category, IFEval is the benchmark that creates the most daylight between them.
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