Set the sample Interval
The sample interval specifies the frequency in which the selected resource is monitored. By default, the sample interval is every 10 seconds. Use the Refresh pull-down menu to set the sample interval from anything between once every 1 second to every 10 minutes.
If you have multiple Dashboard pages open in separate tabs or windows, changing the sample interval on one page will not change the interval on the other pages. However, if you switch between pages in the same browser tab or window, the interval will be the same for all pages.