Batch Ripping on Nimbie

I am using dBpoweramp batch ripper from my Nimbie and CD Ripper with the internal DVD on my PC. The batch takes many hours on a large number of CD to rip or before they are rejected. I am using the settings that came by default. Assuming the batch ripper is using the same options as those for CD Ripper, it is set to secure ripping not burst ripping. As stated, all settings are the default in CD ripper options. In CD Ripper it show the frames which are being re-ripped to help make a determination of how long it may take and if it should be skipped. What setting would you suggest to limited the time for each CD to be no more than half an hour?