(git) clearcase speed

from http://permalink.gmane.org/gmane.comp.version-control.git/132311,
in response to someone touting CC's ability to track partial repos and
asking why git can't do that:

> My (limited) experience with ClearCase is that it's so slow that you'd do *anything* to track fewer files in your working copy, so they put a lot of work into exactly that, and no work into performance.