Compare / o4 Mini vs grok-4-fast-reasoning

o4 Mini vs grok-4-fast-reasoning

12 results from 3 sources that measured both models. Each row is in the source's own units; there is no overall winner.

o4 Mini
OpenAI · profile
grok-4-fast-reasoning
xAI · profile
Results compared
12
Shared sources
3
BenchmarkMetrico4 Minigrok-4-fast-reasoning
Arena (formerly LMArena)reportedOverallArena rating 1,3681,417
Arena (formerly LMArena)reportedBusiness, management and financeArena rating 1,3791,403
Arena (formerly LMArena)reportedCreative writingArena rating 1,3371,383
Arena (formerly LMArena)reportedExpert promptsArena rating 1,4081,421
Arena (formerly LMArena)reportedInstruction followingArena rating 1,3691,389
Arena (formerly LMArena)reportedOverallArena rating 1,3911,405
Arena (formerly LMArena)reportedWriting, literature and languageArena rating 1,3541,388
UGI LeaderboardreportedRequested-length error% off the requested word count 19.0%23.0%
UGI LeaderboardreportedStyle adherencescore from 0 to 1 0.330.33
UGI LeaderboardreportedWriting scorescore out of 100 46.953.4
Vectara Hallucination LeaderboardreportedAnswer rate% of documents 98.7%99.5%
Vectara Hallucination LeaderboardreportedHallucination rate% of summaries 18.6%20.2%

Bold green marks the better value on that metric. Where a source reports ranges that overlap, the difference may not be meaningful; see the benchmark page for ranges.