You should consider more variables tham problem properties. The computation time is affected with hardware too, like thread count, speed of CPU, speed of IO. Iterations count can be too overhead in case of very big problems, you should use time termination in case of big data. Next case can be randomly step on best solution in seaching space, so you should consider using some of variation termination algorithm.
You can look here:
and here is some proposal for termination algorithm: