Conversion of Characteristic Values to SIDs is taking long time

Hi Experts,

Cube load is taking more than 7 hrs to complete for 6 million records. Max time is at Conversion of Characteristic Values to SIDs. Cube consists of 500 fields. Load is from DSO to Cube. DSO has 10 fileds with no SID flag check for activation. Remaining fields in the CUBE are pouplated looking in to other DSO's. Start and End routines are executing very fast. How to fasten Conversion of Characteristic Values to SIDs step. I need to load 15 million records daily as part of delta. any suggestions.

Thanks

Sunil