Specifications

24 Product Errata
25759 Rev. 3.79 July 2009
Revision Guide for AMD Athlon™ 64 and AMD Opteron™ Processors
58 Memory Latency with Processor Power States
Description
If CPU Low Power mode is enabled in the C1, C2, or throttling processor power states, then
externally generated sequences of memory references may experience unexpectedly large latencies
through the memory controller.
Potential Effect on System
Long memory latencies may lead to performance anomolies or functional failures, depending on the
buffering capabilities of external devices.
Suggested Workaround
Do not enable CPU Low Power mode in the C1, C2, or throttling processor power states. Specifically,
disable the CPULowPwrEn bits for System Management Action Field (SMAF) codes 000, 101, and
111 by clearing Dev:3x80[0] for C2, Dev:3x84[24] for C1, and Dev:3x84[8] for throttling.
Fix Planned
Yes