Increase performances on Windchill filtered extraction

Version: Windchill 12.0

Use Case: We are going to migrate a portion of Windchill data from source system (version 12.0) to target system (green-field installation in version 13.0) using WBM (in filtered extraction mode), in order to extract just objects contained in a specific subset of containers (products and libraries). Business object data to be migrated mainly include WTPart, WTDocument, EPMDocument and ECM objects.

Description:

We are facing with performance issues, partially resolved with db and server tuning.
Do anyone with experience on this scenario (filtered extraction)?