Could you try disabling UCC option in you Bios if it is enabled (your processor is AM2 socket processer)
This below is the excerpt from the Manual..
Unlock CPU Core
UCC (Unlock CPU Core) feature simplifies AMD CPU activation. As long as a simple switch of the BIOS option “Unlock CPU Core”, you can unlock the extra CPU core to enjoy an instant performance boost. When UCC feature is enabled, the dual-core or triple-core CPU will boost to the quad-coreCPU, and some CPU, including quad-core CPU, can also increase L3 cache size up to 6MB, which means you can enjoy the upgrade CPU performance with a better price. Please be noted that UCC feature is supported with AM2+ / AM3 CPU only, and in addition, not every AM2+ / AM3 CPU can support this function because some CPU’s hidden core may be malfunctioned..