The amount of time it takes to install the Solaris 9 MU4 varies, depending on the following factors:
CPU speed of your machine
install_mu option that you select
Transfer speed of the hard drive or network that you use to access the install_mu code and patch set
If you install the MU4 with the -d option disabled, the installation proceeds more quickly. However, if you use this option when you install the MU, you cannot back out any of the patches MU4 delivers.