MSGraph Email Poller

we recently implemented a process to read emails from an outlook inbox using the MSGraph email poller detailed here: https://community.appian.com/b/appmarket/posts/msgraph-email-poller

after implementing we're seeing severe performance issues where the poller is only able to process one email per minute.

the emails have a 1mb attachment, and per the documentation, we are expecting 30-50 emails per minutes at the very least.

does anyone have any insights they can share to get around this performance issue? 

thanks!