On 08/12/2009 01:34 AM, Ian Murray wrote: ... > Under Ubuntu (NB the drive was under /dev/sdb under Ubuntu - is this a clue?!?):- Some HP machines have the same symptoms you describe: Slow disk IO with CentOS, fast with Fedora. The cure is to append hda=noprobe hdc=noprobe to the startup parameters in /boot/grub/grub.conf. Mogens -- Mogens Kjaer, Carlsberg A/S, Computer Department Gamle Carlsberg Vej 10, DK-2500 Valby, Denmark Phone: +45 33 27 53 25, Mobile: +45 22 12 53 25 Email: mk at crc.dk Homepage: http://www.crc.dk