Why is the CPU usage so high?

If you notice a very high CPU usage even though the number of Virtual Users remains small, it may be that one of the regular expressions used in a Variable Extractor is too demanding. To find out which regular expression is causing the problem, you can replay the scenario several times, taking out a different regexp on each run until a normal CPU usage is restored. A very simple, downloadable freeware program exists that can help you construct your regular expressions (http://www.weitz.de/regex-coach).