Hi, I have updated the kernel to 2.4.21-27.0.2 on Centos 3.4 (was 3.3 when I did the kernel update) and have modified grub.conf to use the single CPU kernel: # grub.conf generated by anaconda # # Note that you do not have to rerun grub after making changes to this file # NOTICE: You have a /boot partition. This means that # all kernel and initrd paths are relative to /boot/, eg. # root (hd0,0) # kernel /vmlinuz-version ro root=/dev/cciss/c0d0p6 # initrd /initrd-version.img #boot=/dev/cciss/c0d0 default=1 timeout=10 splashimage=(hd0,0)/grub/splash.xpm.gz title CentOS (2.4.21-27.0.2.EL) root (hd0,0) kernel /vmlinuz-2.4.21-27.0.2.EL ro root=LABEL=/ initrd /initrd-2.4.21-27.0.2.EL.img title CentOS (2.4.21-27.0.2.ELsmp) root (hd0,0) kernel /vmlinuz-2.4.21-27.0.2.ELsmp ro root=LABEL=/ initrd /initrd-2.4.21-27.0.2.ELsmp.img title CentOS (2.4.21-27.0.1.EL) ....... I then created a new symbolic link for Sytem.map in /boot to point to System.map-2.4.21-27.0.2.EL. When I reboot the 2.4.21-27.0.1.ELsmp is used and System.map has been changed to point to the smp kernel. Is there a step I'm missing out? BTW, the upgrade from 3.3 to 3.4 using yum seems to have worked - I'm running Oracle on the server. Thanks, Wayne