Help on the intel dx58so motherboard

[NYRAD]

hi guys i have a intel dx58so smackover x58 motherboard and i want to know how do i set my 21x multiplier in the bios without turning on eist :( as when it is on and i run prime it throttles to 20x is there anyway to bypass this i have a 920 DO step cpu will post my batch a bit later as im at work lol
thanks for the help in advance