Most of my build configurations contain two SVN roots:
The first SVN root points to a SVN module that is our IVY repository where we house all our third-party libraries and all of our internally generated artifacts. The second SVN root points to a SVN module that contains the project being built.
When a build is initiated, it will sit for minutes just checking out the IVY repository and then the same for the project. For example, if i execute the ant target from within the IDE, it runs in 24 seconds; however executing the same ant target under TC takes over 2 minutes--this is for only 40 tests. I have another project with a little over 700 tests that runs in a couple of minutes under the IDE but takes ~20 minutes under TC.
BTW, it has been this way since the 1.2 release ...