Compare / Claude Opus 4.5 vs grok-4-fast

Claude Opus 4.5 vs grok-4-fast

3 results from 2 sources that measured both models. Each row is in the source's own units; there is no overall winner.

Claude Opus 4.5
Anthropic · profile
grok-4-fast
xAI · profile
Results compared
3
Shared sources
2
BenchmarkMetricClaude Opus 4.5grok-4-fast
Arena (formerly LMArena)reportedOverallArena rating 1,1871,160
tau2-benchreportedConsistency (pass^4)% of tasks 11.3%4.1%
tau2-benchreportedTask success (pass^1)% of tasks 24.7%15.7%

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.