Thanks for pointing that out Lsdmeasap
That has answered a question I have posted on a number of forums regarding boot-up behaviour with these boards. My X58A-UD3R always starts/stops/starts & boots if I switch on my system after the power has been switched off at the socket or PSU - even with Optimised Settings.
It sounds as though not everyone has this behaviour, but its fairly common with intel chipsets.
Until now, nobody has actually came out and said that it is not a faulty component, but just a quirk.
Cheers