This paper provides an overview of a flow to generate and apply cache-resident self-test (CReST) patterns on a CPU as an alternative to deterministic functional patterns. This paper also compares CReST patterns against deterministic functional patterns, including the results of a case study of applying both CReST and deterministic functional patterns on commercially available AMD x86 processors in highvolume production. The experiment indicates that CReST patterns are an effective substitute for functional patterns.