The IBM eServer z990 microprocessor implements many features designed to give excellent performance on both newer and traditional mainframe applications. These features include a new superscalar instruction execution pipeline, highbandwidth caches, a huge secondary translation-lookaside buffer (TLB), and an onboard cryptographic coprocessor. The microprocessor maintains zSeries leadership in RAS (reliability, availability, serviceability) capabilities that include state-of-the-art error detection and recovery.