[otrs] Massive Email Fetch Problem

Hi I have installed OTRS 3.1.4, works great I used the web based configuration for fetch mails via POP3. In some cases we have massive events, around 5000 mails in ten minutes, but OTRS take about five hours to fetch all emails. How I can define the amount of fetch mails for request? I want configure the bash script, but never works for me... official documentation do not show where the mails are stored. Thanks