posting inserts to remote DB2 database

Got some very odd things happening here. If I write an app to post to DB2 (monkeybread plugin) one exe can only insert 200 records a second (with 1000 records per transaction). If I run the exe 10 times I get in total 2000 a second. Why would one process (connection) socket, limit the posting by a factor of 10?
Anyone any ideas.