whats the difrence bewtten the high end procs?

well basicly whats the difrence bewtten a fx55 and a fx57, they have the same cores, and dont they have unlocked multys? or was that jsut something i herd? so yeah,

im getting my phase change done soon, and im dont think my opty148 is going to rellly run. so after i get my cooler done, im going to get a new proc. just curios of what you guys think is a good choice. thanks
evil

The FX57 comes stock at 2.8Ghz and the FX55 comes stock at 2.6Ghz. The 57 usually clocks a little higher than the 55 does.