Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.
GPT-5.1-Codex-Max is clearly ahead on the aggregate, 84 to 33. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.1-Codex-Max's sharpest advantage is in coding, where it averages 75.5 against 8.2. The single biggest benchmark swing on the page is HumanEval, 94 to 17.
GPT-5.1-Codex-Max is also the more expensive model on tokens at $2.00 input / $8.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for LFM2.5-1.2B-Thinking. That is roughly Infinityx on output cost alone. GPT-5.1-Codex-Max gives you the larger context window at 400K, compared with 32K for LFM2.5-1.2B-Thinking.
Pick GPT-5.1-Codex-Max if you want the stronger benchmark profile. LFM2.5-1.2B-Thinking only becomes the better choice if you want the cheaper token bill.
GPT-5.1-Codex-Max
86
LFM2.5-1.2B-Thinking
34.1
GPT-5.1-Codex-Max
75.5
LFM2.5-1.2B-Thinking
8.2
GPT-5.1-Codex-Max
88.2
LFM2.5-1.2B-Thinking
32.4
GPT-5.1-Codex-Max
92.1
LFM2.5-1.2B-Thinking
38.4
GPT-5.1-Codex-Max
72.6
LFM2.5-1.2B-Thinking
27
GPT-5.1-Codex-Max
91
LFM2.5-1.2B-Thinking
72
GPT-5.1-Codex-Max
87.7
LFM2.5-1.2B-Thinking
60.7
GPT-5.1-Codex-Max
94.9
LFM2.5-1.2B-Thinking
42.3
GPT-5.1-Codex-Max is ahead overall, 84 to 33. The biggest single separator in this matchup is HumanEval, where the scores are 94 and 17.
GPT-5.1-Codex-Max has the edge for knowledge tasks in this comparison, averaging 72.6 versus 27. Inside this category, MMLU is the benchmark that creates the most daylight between them.
GPT-5.1-Codex-Max has the edge for coding in this comparison, averaging 75.5 versus 8.2. Inside this category, HumanEval is the benchmark that creates the most daylight between them.
GPT-5.1-Codex-Max has the edge for math in this comparison, averaging 94.9 versus 42.3. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.
GPT-5.1-Codex-Max has the edge for reasoning in this comparison, averaging 92.1 versus 38.4. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.
GPT-5.1-Codex-Max has the edge for agentic tasks in this comparison, averaging 86 versus 34.1. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
GPT-5.1-Codex-Max has the edge for multimodal and grounded tasks in this comparison, averaging 88.2 versus 32.4. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.
GPT-5.1-Codex-Max has the edge for instruction following in this comparison, averaging 91 versus 72. Inside this category, IFEval is the benchmark that creates the most daylight between them.
GPT-5.1-Codex-Max has the edge for multilingual tasks in this comparison, averaging 87.7 versus 60.7. Inside this category, MGSM is the benchmark that creates the most daylight between them.
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