The brain learns statistical regularities in sensory sequences, enhancing behavioral performance for predictable stimuli while impairing behavioral performance for unpredictable stimuli. While previous research has shown that violations of non-informative regularities hinder task performance, it remains unclear whether predictable but task-irrelevant structures can facilitate performance. In a tone duration discrimination task, we manipulated the task-irrelevant pitch dimension by varying transition probabilities (TP) between successive tone frequencies. Participants judged duration, while pitch sequences were either deterministic (a rule-governed pitch pattern, TP = 1) or stochastic (no discernible pitch pattern, TP = 1/number of pitch levels). The tone pitch was task-irrelevant and it did not predict duration. Results showed that reaction times (RTs) were significantly faster for deterministic sequences, suggesting that predictability in a task-irrelevant dimension still facilitates task performance. RTs were also faster in two-tone sequences compared to eight-tone sequences, likely due to reduced memory load. These findings suggest that statistical learning benefits extend beyond task-relevant dimensions, supporting a predictive coding framework in which the brain integrates predictable sensory input to optimize cognitive processing.