Searching is slow in Outlook Web App (Exchange 2010)

[adamf]

Having recently upgraded to Exchange 2010 an issue has been highlighted by some of our staff that searching is very slow and results are not displayed when searching using Outlook Web App. If you enter a search term and wait for the searching dialog box to apper, then click refresh, the results are displayed - but they never seem to appear on there own.

 

Does anybody have any ides why this might be?