A superscalar CPU can execute more than one instruction per clock cycle. Because processing speeds are measured in clock cycles per second (megahertz), a superscalar processor will be faster than a scalar processor rated at the same megahertz.
A superscalar architecture includes parallel execution units, which can execute instructions simultaneously. This parallel architecture was first implemented in RISC processors, which use short and simple instructions to perform calculations. Because of their superscalar capabilities, RISC processors have typically performed better than CISC processors running at the same megahertz. However, most CISC-based processors (such as the Intel Pentium) now include some RISC architecture as well, which enables them to execute instructions in parallel. Nearly all processors developed after 1998 are superscalar.