Phenom CPU have two individual memory controllers (DCTs), each one of them controls single memory channel (64 bit). These two DCTs can work simultaneously when memory modules are installed on different memory channels. It is called “unganged mode”.

You can switch to “ganged mode, 128bit” when you are using two or four of the same memory modules. Please kindly enter BIOS setup program, to press CTRL+F1 key to enable advanced BIOS setup features then enter "MB Intelligent Tweaker(M.I.T.)\ DRAM Configuration", to set the “DCTs Mode” as “Ganged”.