i had an issue once where the setup wouldnt go past a certain bus and thought it was odd...had to clean and remount the CPU.

you seem to be having issues with the bus so try working on that first with lower multi. Might as well remount and don't evertighten. Also just for starters OC with one stick of RAM and then put the rest in.

go through the list of options in bios that you are changing...