The cvs2svn test suite, which runs reliably under Linux + Python 2.4/2.5 + Subversion 1.5, fails when run under psyco:
$ svn checkout http://cvs2svn.tigris.org/svn/cvs2svn/trunk cvs2svn --username guest
$ cd cvs2svn
# Add lines to cvs2svn script to fire up psyco
# Test 77 is a simple test from our test suite that fails:
$ ./run-tests.py 77
[...]
cvs2svn_lib.common.InternalError: ID...
2009-07-25 17:25:59 UTC in Psyco, the Python Specializing Compiler