What is your ram voltage set to in the bios, as you may need to raise it.
L2 cache is something to do with cpu isn't it?
what bios you on? f12?
Dont know, it passes the cpu test in bois so i would think the cpu is ok with the board but i may pick up a cheap i7 and see if i need to flash bios
manual says it has dual bios, tried the other one?