For a long time I wondered why it took minutes from the time I clicked
on a URL in an e-mail (Thunderbird) until the web page opened in Firefox.
I investigated several counters in the performance monitoring utility,
and finally discovered that the counter called "% of Maximum Frequency"
kept ratcheting up to 100%. See http://web.ncf.ca/~ff293/Images/For Newgroup.png
I can't find a good description of what this counter really indicates.