Barely a week after the introduction of new Phenom II processors for the AM3 socket, reports are beginning to emerge about an alleged bug within the DDR3 memory sub-system. Specifically, a revision guide document for the processor mentions that on machines with more than one DDR3-1333 (or greater) memory modules installed per channel, users may experience "unreliable operation."
Without getting into the specifics of the symptoms, AMD's Damon Muzny has acknowledged this issue, and also took the time to clarify the situation. According to him, internal testing showed that with certain lower quality memory modules and all four slots populated (2 modules per channel), inter-component signaling could become erratic and result in system instability. Muzny says they were faced with a choice: to either drop listing support for DDR3-1333 altogether or design the system to down clock the memory to 1066 - they took the most conservative approach and went with the latter to ensure stability.
He went on to suggest how users could manually configure memory to compensate for the slight drop in performance and assured customers that the issue is of a software nature and that it will be fixed shortly.