Just to toss out a little good info. Got 3 555 Mbox c3 CPUS from a microcenter and all 3 unlocked all 4 cores and oc'd them to 3.9 @ 1.475-1.485 volts primed for 5 hours at 44c. Non would hold 4g up to 1.535. I wont go higher then that for 24.7 voltage. So 3.9 is very good. I did get them to post up to 4.5g. Havent tested to see if they are at least bench stable up that high yet though. These 555 c3's look to be a killer deal. BTW, im using Asus M4A79XTD EVO mobo with newest bios.