Yup fresh reboots all round.
Just to be clear my "10 - 15% all up" while running Vbox includes running two large monitors, 4 desktops, (Compiz), quite a few plasmoid thingies and several programs open full time, (Thunderbird, Audacious etc etc). With everything at rest Vbox only adds a few % of cpu cycles.
The slow down came as a result of installing the XP image on another physical hard drive.......... and it wasn't the result I expected.
I didn't even bother seeing if XP on the new setup was actually faster, (not that I would be able to tell as it is visually quicker than the host anyway..... oops I never said that
). I rebooted a few times to check the excessive cpu usage at rest, it didn't float my boat at all so back to the old set up. I keep Vbox/XP running in the background pretty much continuously due to the nature of my work and although it's winter here in NZ I can think of better ways of heating the room
I did check within XP itself to see if some program was causing the slowdown but couldn't find any culprits. My next job will be to strip XP down to the absolute bare minimum with XPLite, (it really flies then), with a backup copy handy as unlike in Vmware I can't use a NAT connection out to the internet and have to use a Bridged which from my reading isn't all that secure so just like any window, when it breaks you just replace it.
anyway I'm beginning to waffle a bit, time to close, have another wine and will post if I figure out the shutdown situation. Thanks for the input.