Consider using file geodatabase instead of personal geodatabase
In Arcmap The personal geodatabases are implemented with Microsoft Access databases. Unfortunately they limit the size of the processed dataset. There is a limit of ~2GB for a geodatabase. Additionally it looks like other limits (did not verify) related to Microsoft Access database must also be acting because we hit the limit sometimes before the size limit is reached. Is there a specific reason for using a personal geodatabase? If not, consider switching to use of file geodatabases to support one-step processing of large datasets.