This week TechARP's BIOS Option Of The Week is Asynclat, full details over here.
Since 1999, we have been developing the BIOS Optimization
Guide, affectionately known as the BOG. From a meager beginning of a
single page, it now covers over 440 BIOS options. As old BOG readers
will know, we started offering two editions of the BOG since Revision
8.0 - a simplified edition and the complete edition.
This is an AMD Athlon 64 / Opteron processor-specific BIOS feature. It controls the amount of asynchronous latency, which depends on the time it takes for data to travel from the processor to the furthest DIMM on the motherboard and back. For your reference, AMD has a few conservative suggestions on setting this BIOS feature.