Specifications

Product Errata 41
Revision Guide for AMD Athlon™ 64 and AMD Opteron™ Processors
25759 Rev. 3.79 July 2009
79 Power Management Limitations Above 1.50V
Description
Processor versions with a core voltage greater than 1.50V do not support Northbridge low power
mode while in the S1 power state or LDTSTOP_L initiated HyperTransport link width/frequency
changes.
Potential Effect on System
Unpredictable system failures may occur.
Suggested Workaround
For affected versions of the processor, do not enable Northbridge low power mode in the S1 power
state. Specifically, clear the NBLowPwrEn bit in SMAF code 011 of the Power Management Control
Registers (i.e., clear Dev:3x80[25]).
Also, use warm reset (rather than LDTSTOP_L) to initiate HyperTransport link width/frequency
changes.
Fix Planned
Yes