17% after 10 hours is very bad. You may want to check your power saving options and make sure that "turn off hard disks" is set to never, since having this option turned on can really slow down your times. Also setting the client to run always, turning off the screen saver, adjusting your RAM's CAS setting to 2, or switching to the commandline client can speed up your times. As an example of some times my Pentium 2 400 averages 13hr/WorkUnit. my Pentium 3 933@1000 averages 6.25hr/WU, and my Athlon XP 1800+ gets about 4hr/WU.