Performance problem: Loading data via insert

We are facing a performance problem but unable to identify where is the problem.

We have a production database server where about 8 database instances of oracle is running. Daily we insert in each of these database instances about 1-5 GB of data in different tables. All database instances are working fine where we are able to load around 2-3 GB of data within 1hour except 1 where it is taking about 8 hrs to load only 4 GB of data.

When I try to load the same 4GB of data in another database where only one instance is running and with very less configuration as compared to the Production server we were able to load it in 1hr 45 minutes.

Can anyone suggest how can we proceed to identify the problem?

Regards
Abhishek                                                

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