 The VIA Cyrix III and VIA C3 CPUs offer 8 Intel-style MTRRs.The memory interface of AMD K8 CPUs supports "Extended fixed-range MTRR Type-Field Encodings" which allows one to specify whether accesses to certain address ranges are executed by accessing RAM through the Direct Connect Architecture or by executing memory-mapped I/O.This allows, for example, shadow RAM to be implemented by copying ROM contents into RAM.