mingdao@silas:~$ time tar xjf linux-2.6.24.tar.bz2

real    0m39.722s
user    0m22.159s
sys     0m2.281s

mingdao@silas:~$ time tar xvjf linux-2.6.24.tar.bz2

real    0m45.794s
user    0m23.095s
sys     0m2.570s