Delays are expected when searching for multiple days worth of SMTP, IMAP, EAS, or a variety of other logs due to the amount of data contained here. Finding and relating all of this information can take some time to render, but more importantly can take some time to seek from disk. As such, you will likely always see small delays here, but I believe you can limit them by doing the following: 

- Implement Normal logging instead of Detailed. 

- Run SmarterMail logs on an SSD-backed storage system for quickest I/O times.