I am having serious performance problems with NTA3 SP1. This was also occurring on SP0. When I open NTA to the summary screen, it takes a very long time to complete rendering the page. Sometimes I get the dreaded Stacked Chart Error. In addition, sometimes I get blank slots where graphs should be and the "Report loading cancelled" error. When I try drilling down to look at a single domain or node details, almost all of the graphs do not come up and display the "Report loading cancelled" message. I have opened a ticket on this, #46329, but so far, no help.
In addition, I frequently get the dreaded HTTP.Exception when the entire page times out. I have also had several incidents where the whole database goes into recovery and I get an error box that NPM cannot connect to the database.
So far, I have had so much trouble with NTA 3 I am considering uninstalling it and going back to V2. Although I got the Stacked Chart Errors with 2, I was able to drill down and get detailed information without much of a problem.