THis I have found is one of the best guides to your bios and what the settings mean.

http://www.adriansrojakpot.com/Speed_Demonz/New_BIOS_Guide/Index.htm

http://www.adriansrojakpot.com/Speed_Demonz/BIOS_Guide/BIOS_Guide_Index.htm

I think it may be a bios issue- you should possibly check for a bios update- I don't recomend flashing them unless you know what you are doing but- possibly have a look at your motherboard manufacturer site and see if there is possibly a bios update