Another good indicator of individual performance is on any form within ServiceNow itself. This indicates where your delay was in opening the form, in this instance you see it took over 3 seconds of server time processing this form. I say this is useful because almost all of the time when a user is complaining of performance, the issue is the browser timer you see below, meaning it's a problem on the pc, not necessarily with ServiceNow itself.

Here's link to ServiceNow's wiki on performance troubleshooting as well: Troubleshooting Performance - ServiceNow Wiki