The Intel Pentium Pro processor is used on all the nodes in the ASCI option red supercomputer. The Intel Pentium Pro processor is both a CISC and a RISC chip. Its instruction set is essentially the same as that for the Pentium processor. At runtime, however, the CISC instructions are broken down into simpler, RISC instructions called micro-operations (or uops). The uops execute in a RISC core inside the Pentiumâ Pro processor with the order of execution dictated by the availability of data. This lets the CPU continue with productive work when other uops are waiting for data or functional units. This out of order execution is combined with sophisticated branch prediction and register renaming to provide what Intel calls, dynamic execution.