Cheers Keyser,
I come bearing good news, after request some technical support I got some advice from the RMA team and got a result.
They advised me to up the Northbridge voltage a bit, I increased it from 1.10v to 1.20v and got a result.
I think the problem is something to do with the IDE controller, both the Optical drives I have plugged seem to hang for an age and then go berserk and spin up.
Will replace them and see what happens, but for the time being I am happy.
Thanks OCUK!
Stedders