The maximum number of iterations to use for each customer sample is configurable using the Optimize|AlgorithmTuning|MaxIterationsPerCustomerSample property. Check both the session level advanced settings and the configuration properties.
To analyze the customer sample iteration behavior, search in the Contact Optimization log for the string
Iteration:. This log entry is followed by a number, indicating which iteration it is. Each chunk starts at iteration 1 and counts up. It helps to see what is going on if you get a count of each iteration number in the log, and use the results to construct a histogram.
Another major factor in performance is the number of unprocessable customers. If the value of the Optimize|AlgorithmTuning|MaxAlternativesPerCustomerEvaluated property is a large number (over 100 or so), the time penalty is high whenever a customer is unprocessable.
In Contact Optimization version 7.5.3 and later, there is more detailed logging to show the minimum, maximum, and average number of alternatives evaluated for each customer sample.