Exchange job is running very slowly.
In some cases we have found that Exchange performance can be increased significantly by selecting the particular database(s) for a job and not just the mail server itself.
Selecting the mail server appears to cause it to hit both causing it to do twice the work.
If you have multiple servers the standard advice of separate workers or separate jobs still applies.
This article was originally published in the GWAVA knowledgebase as article ID 2410.