In this paper, we present application of the SDL technique towards full root cause analysis of functional and structural failures from BIST, SCAN etc. on AMD’s advanced Silicon-on-Insulator (SOI) microprocessors based on a 90 nm process technology node. The devices were exercised at speed using production testers. SDL is used on these microprocessors with failure modes which pass at a lower temperature/voltage but fail at higher temperature/voltage or vice versa to isolate the failing logic/node. The SDL sites are examined for a full root cause analysis and possible process improvements.