The online class imbalance and concept drift (OCI-CD) has recently received much interest. The impact of this combined problem on state-of-the-art of online adaptive and non-adaptive learners has received little attention. This study investigates the effect of parameters such as current imbalance ratio, stream length, drift type, drift levels, and imbalance state (static or dynamic) on adaptive and non-adaptive online learners. The experimental results show that each parameter considered for the study has a significant impact on learner performance: (a) minority class performance decreases as the degree of imbalance increases, (b) non-adaptive learners are much susceptible to class imbalance, concept drift, and the combined problem of both drifts than adaptive learners, (c) adaptive learners are only susceptible to class imbalance drifts, and (d) the impact of the dynamic degree of imbalance is more on learner than static (e) the adaptive large scale support vector machine yields stable performance to all the parameters considered for the study. Based on these findings, directions for developing new approaches are also presented. Povzetek: Analizirane so razne metode strojnega učenja glede na parametre učenja, recimo spreminjanje neuravnoteženja razredov.