The default field that it matches on seems to be account name. This is not working well for us and resulting in more than 10,000 duplicate Accounts. I would like to change it to match on a custom field I have. Where do I go in the settings to configure Leads module to match to Accounts module on a different field?

I should clarify the question.

When a Lead is converted to a Contact, CRM attempts to match both Account and Contact. It is looking for an existing Contact based on email address, which is working great. However, when it looks for an existing Account it is checking the Account Name. I have a unique, standardized custom field that I would like to use for CRM to find existing Accounts instead of Account Name. This would result in much greater accuracy in matching, and significantly reduce the number of duplicate Accounts created.