the MoBo is a Gigabyte X58A-UD3R Rev 1.0, bought early in 2010.
I have tried the "MoBo number" and "problems" in the various search engines, didn't find any issues anything like I am seeing. A number of people were having fun and games with amount of installed RAM not being reported by the system, I have not seen this. If I change the number of sticks fitted it flags up correctly in the POST (if you can read it quickly enough. It is possible that I have an obscure one off fault. If it runs for many hours/days without showing it would probably pass the manufacturer end of production line tests OK.
If I reset the CMOS, as has been suggested, what will that affect? What might it mess up?
In previous reply I put in the system shut down time of 12 seconds when I meant to put in 42 seconds boot up time, duh.
Thanks for your continuing assistance.
Rans6...........