Deadlocks and Timeouts occurring in multithreaded batch delete application

Hi,

We have a requirement to delete records(nearly 0.4 million) quickly from CRM 2011.I have written an application that deletes records using multithreading.While executing batch delete using mutithreading, deadlocks and timeouts are occurring.

It deleted fine without multithreading but it is taking very long time.Hence tried to use mutithreading to speedup the deletion.

Can any one help me on this issue?

Thanks in advance

Swathi