I don't think it is the CPU... with 1.25v it should have not failed at stock speed.
Please tell us your computer specs (Motherboard, Video Card, Memory, PSU, etc)
Maybe it is as Nxl8 said and it is the memory. I don't know if AMD memory has XMP settings so just to be sure if you have 4gb 1333Mhz go into the BIOS in AI Tweaker -> Check if Target DRAM Speed is 1333MHz (if not set it to 1333MHz in Memory Frequency), then go to DRAM Timing Control and set the first 3 option from auto to 9, the 4th to 24 and leave the last one in auto. Then go back and set DRAM Voltage to 1.5V. Press F10, save and test again.
Edit: I forgot, put the CPU voltage to auto again