Performance issue extraction of data from the planning area outbound cube

In our DP implementation we have made an outbound cube and we have apporx 100,000 CVC with 20 key figures. We are facing problems in extracting the data from the planning area into our outbound cube (using BI7). I think that the number of CVC is too low to give a performance issue but the data extraction never ends.Even when we try to extract only one key figure we are still facing a lot of performance issues.

Could any one please tell me what might be the problem in here. Do you guys think aggregation of data at particular characteristics might be the solution.

Thanks in advance