Actually any 790G chipset based board with Advance Clock Calibration function enabled, supports enabling of the 4th core of the Phenom II X3 processors. But it also depends upon ur processors. Some batch of the Phenom II X3s are having a not fully damaged 4th core. Only they can be enabled. They may have some faulty register or some portions of the Cache disabled, but still in a workable condition. If the 4th core is highly damaged, then it may not be possible to enable it.